Nuclear fission reactor, a vented nuclear fission fuel module, methods therefor and a vented nuclear fission fuel module system

ABSTRACT

Illustrative embodiments provide a nuclear fission reactor, a vented nuclear fission fuel module, methods therefor and a vented nuclear fission fuel module system.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to and claims the benefit of theearliest available effective filing date(s) from the following listedapplication(s) (the “Related Applications”) (e.g., claims earliestavailable priority dates for other than provisional patent applicationsor claims benefits under 35 USC §119(e) for provisional patentapplications, for any and all parent, grandparent, great-grandparent,etc. applications of the Related Application(s)). All subject matter ofthe Related Applications and of any and all parent, grandparent,great-grandparent, etc. applications of the Related Applications isincorporated herein by reference to the extent such subject matter isnot inconsistent herewith.

RELATED APPLICATIONS

The present application constitutes a continuation-in-part of U.S.patent application Ser. No. 12/584,053, entitled A NUCLEAR FISSIONREACTOR, A VENTED NUCLEAR FISSION FUEL MODULE, METHODS THEREFOR AND AVENTED NUCLEAR FISSION FUEL MODULE SYSTEM, naming Charles E. Ahlfeld,Pavel Hejzlar, Roderick A. Hyde, Muriel Y. Ishikawa, David G. McAlees,Jon D. McWhirter, Nathan P. Myhrvold, Ashok Odedra, Clarence T.Tegreene, Joshua C. Walter, Kevan D. Weaver, Thomas Allan Weaver,Charles Whitmer, Lowell L. Wood, Jr., and George B. Zimmerman asinventors, filed Aug. 28, 2009, or is an application of whichapplication is entitled to the benefit of the filing date now U.S. Pat.No. 8,488,734.

The United States Patent Office (USPTO) has published a notice to theeffect that the USPTO's computer programs require that patent applicantsreference both a serial number and indicate whether an application is acontinuation or continuation-in-part. Stephen G. Kunin, Benefit ofPrior-Filed Application, USPTO Official Gazette Mar. 18, 2003.

BACKGROUND

This application generally relates to induced nuclear reactionsincluding processes, systems and elements, wherein a fuel componentincludes a means to release fission products therefrom during normaloperation of a nuclear reactor and more particularly relates to anuclear fission reactor, a vented nuclear fission fuel module, methodstherefor and a vented nuclear fission fuel module system.

It is known that, in an operating nuclear fission reactor, neutrons of aknown energy are absorbed by nuclides having a high atomic mass. Theresulting compound nucleus separates into about 200 fission products(i.e., a residual nucleus formed in fission, including fission fragmentsand their decay daughters) that include two lower atomic mass fissionfragments (i.e., a nucleus formed as a result of fission) and also decayproducts (a nuclide resulting from radioactive decay of a parent isotopeor precursor nuclide). Nuclides known to undergo such fission byneutrons of all energies include uranium-233, uranium-235 andplutonium-239, which are fissile nuclides. For example, thermal neutronshaving a kinetic energy of 0.0253 eV (electron volts) can be used tofission U-235 nuclei. Fission of thorium-232 and uranium-238, which arefertile nuclides, will not undergo induced fission, except with fastneutrons that have a kinetic energy of at least 1 MeV (million electronvolts). The total kinetic energy released from each fission event isabout 200 MeV for U-235 and about 210 MeV for Pu-239. In a commercialnuclear fission power reactor, this energy release is used to generateelectricity.

During reactor operation, the aforementioned fission products may bereleased from a nuclear fuel pellet during the fission process. In thecase of U-235 fission, typical fission products include isotopes of theelements of barium, iodine, cesium, krypton, strontium and xenon, amongothers. Some of these fission products are short-lived, such as I-131which has a half-life of about eight days before beta decaying toXe-131. Other fission products are longer-lived, such as Sr-90 which hasa half-life of about 30 years. Production of solid and gaseous fissionproducts or decay products thereof can affect operation of the nuclearreactor by having adverse effects on cladding material that house aplurality of the nuclear fuel pellets. These effects typically occur dueto stress on the cladding because of increased internal pressure fromthe fission gases, contact of the fuel with the cladding due to swellingof the fuel (also known as fuel cladding mechanical interaction, FCMI),and chemical interactions of the myriad of fission products and existingor formed actinides with the cladding (also known as fuel claddingchemical interaction, FCCI). As an example of the former, fissionproduct gases may accumulate in fuel rods containing the nuclear fueland cause the fuel rod cladding to swell or deform plastically becauseof the increased internal pressure. As an example of FCMI, individualfuel pellets may swell volumetrically either across the entire fuelpellet or at the ends thereof to form an hour-glass shape. The mechanismleading to fuel pellet swelling that can compromise fuel claddingintegrity is reasonably well understood by those in the art. In thisregard, a gaseous fission product isotope may diffuse into the grainboundary of the fuel to form a gas bubble there, which leads, in part,to swelling of the fuel pellet. Additionally, solid phase fissionproducts may precipitate out of the fuel matrix. Such processescontribute to the swelling of the fuel pellets. In either case, suchswollen fuel pellets may bridge a heat transfer gap that is presentbetween the fuel pellets and the cladding surrounding or housing thefuel pellets, thereby allowing the fuel pellets to contact the cladding.Contact of the fuel pellets with the cladding cause stressconcentrations on the cladding as fission products continue to be formedleading to further fuel swelling. Fission products may migrate from thefuel pellet, travel into the heat transfer medium in the gap between thefuel pellet and cladding and may be either absorbed, adsorbed, orinteract chemically with portions of the cladding, particularly at grainboundaries. In other words, the fission products, gaseous or otherwise,may accelerate stress corrosion cracking of the cladding, which may inturn lead to a breach of the cladding at the locally affected areas. Itis understood that fission gas pressure, FCMI, and FCCI may interactupon the cladding in a manner such that the effects are compounded.

As previously mentioned, swelling of the fuel and build-up of fissiongases can exert pressure on the fuel rod cladding that encloses the fuelmaterial. Stresses, unless compensated for, might cause the fuel rodcladding to swell to the extent that coolant flow channels areobstructed. Also, such stresses, unless compensated for, might cause thefuel rod cladding to crack or rupture, as mentioned hereinabove. Thus,during the design phase of a nuclear fission reactor, reactor designersmay shorten the design life of the nuclear fission reactor to compensatefor the effects caused by accumulation of fission product solids andgases. Moreover, during operation of the nuclear fission reactor,reactor operators may be forced to temporarily shut-down the reactor toreplace fuel rods that swell, crack or rupture due to effects of fissionproduct gases.

There are various nuclear power reactor designs currently in use. Eachof these designs produces fission products. For example, a pressurizedwater reactor (PWR) design, which uses thermal energy neutrons, includesa pressurizer that is partially filled with water. The water in thepressurizer is heated to create a steam bubble above the water that isin the pressurizer. The pressurizer, which is connected to a primarycoolant loop of the reactor, provides an expansion space by means of thesteam bubble to accommodate changes in water volume during reactoroperation. Pressure is controlled in the primary coolant loop byincreasing or decreasing the steam pressure in the pressurizer. Also,heat due to nuclear fission is transferred by conduction through thefuel cladding to water circulating in the primary coolant loop. Due to arelatively high pressure of about 138 bars (i.e., 2000 psi) in theprimary coolant loop, coolant boiling is precluded in a PWR. A steamgenerator, that includes a secondary loop as well as the primary looppassing through it, is provided that allows the heat to transfer fromthe primary coolant loop to the secondary coolant loop. The secondarycoolant loop is separate from the primary coolant loop, so that thecoolant flowing through the secondary coolant loop is not radioactivelycontaminated by the radioactive coolant flowing through the primarycoolant loop. Due to the heat transfer occurring in the steam generator,steam that is produced in the steam generator is eventually supplied toa turbine-generator for generating electricity in a manner well known inthe art of electricity production from steam.

Moreover, fuel used in PWRs is typically uranium dioxide (UO₂) sealed ina cladding made from a zirconium alloy, such as ZIRCALOY™ (trademark ofthe Westinghouse Electric Corporation, located in Pittsburgh, Pa.,U.S.A.). For example, a specific cladding material that is in common usedue to its low absorption cross-section for thermal neutrons and knownresistance to corrosion and cracking is ZIRCALOY-2™, which containschromium. A common composition given in the literature for ZIRCALOY-2™contains about 98.25 weight % (wt %) zirconium (Zr), 0.10 wt % chromium(Cr), 1.45 wt % tin (Sn), 0.135 wt % iron (Fe), 0.055 wt % nickel (Ni)and 0.01 wt % hafnium (Hf). However, chemical interaction between thefission product cesium (Cs) and the chromium in the Zircaloy-2™ claddingmay form the corrosion product compound cesium chromate (Cs₂CrO₄) thatmay conceivably attack the cladding. Other fission products, in additionto Cs, known possibly to attack ZIRCALOY-2™ include rubidium, cesiumurinates, cesium zirconates, cesium halides, tellurium and otherhalogens, and fuel pellet impurities such as hydrogen, water andhydrocarbons. On the other hand, the cladding in a PWR may be made frommaterials other than ZIRCALOY-2™, such as ferritic martensitic steels.For example, Type AISI 304L stainless steel, which also containschromium, has been used as another cladding material and contains C(0.02 wt %), Si (0.66 wt %), Mn (1.49 wt %), P (0.031 wt %), S (0.007 wt%), Cr (18.47 wt %), Ni (10.49 wt %) and Fe (68.83 wt %). Thus, thecorrosion product cesium chromate may also be produced when stainlesssteel is used. However, it is known by persons of skill in the art ofnuclear power reactor design that use of ZIRCALOY™, or ZIRCALOY-2™ orferritic martensitic steels, even in the presence of fission productsolids and gasses, reduces the risk of cladding corrosion, cracking orrupture to manageable levels for a given level of burn-up.

A boiling water reactor (BWR) design, which also uses thermal energyneutrons, allows coolant that acts as a moderator of neutrons to boil inthe region of the fuel rods at a pressure of about 60 to about 70 bars(i.e., about 870 psi to about 1015 psi). This steam-water mixture issupplied to a water separator that separates the steam from the water.Thereafter the steam is supplied to a dryer that dries the steam. The“dried” steam is supplied to a turbine-generator for generatingelectricity in a manner well known in the art of electricity generationfrom steam. This reactor design does not use a secondary coolant loop orsteam generator. In some cases, it may be desirable to remove fissionproducts from the coolant, so that fission products do not contaminatethe turbine-generator. The fuel in the fuel rods typically is UO₂ andthe cladding material typically is Zircaloy-2™. Thus, the pellet-cladinteractions mentioned hereinabove for PWRs that might give rise torelease of fission products may also obtain for BWRs. In addition,recirculation pumps may be used in BWRs to force recirculation of thecoolant in order to control reactor power. The power history of thereactor in turn affects the amount and type of fission productsproduced.

A fast neutron reactor (FNR), such as a liquid metal fast breederreactor (LMFBR) design, uses fast energy neutrons rather than thermalenergy neutrons in the fission process. It is known that, in such fastneutron reactors, there is a greater excess of neutrons released duringthe fission process than in thermal neutron reactors. This excess ofneutrons is used to breed fissile material through the absorption of theexcess neutrons in fertile material. More specifically, the reactor coreis surrounded by a blanket of non-fissile fuel materials, such asuranium-238, which is bred, or converted, to fissile fuel material, suchas plutonium-239. The plutonium-239 can be reprocessed for use asnuclear fuel. It is known that such a method to operate and reprocessfuel within certain fast breeder reactors can lead to more fuel producedfrom the system than is consumed. The nuclear fuel present in thereactor core may be a uranium-nitride (UN). On the other hand, the fuelmay be a mixed oxide fuel, such as plutonium dioxide (PuO₂) and uraniumdioxide (UO₂). Alternatively, the fuel may be a metal actinide fuelproduced by neutron capture during the fission process, such as an alloyof zirconium, uranium, plutonium and minor actinides (e.g.,neptunium-237, americium-241, curium-242 through curium-248,berkelium-247, californium-249 through californium-252, einsteinium-252and fermium-257). The reactor core is cooled by liquid metal, such asliquid sodium (Na) metal, or liquid lead metal, or a metal mixture, suchas sodium-potassium (Na—K), or lead-bismuth (Pb—Bi). As is the case withall nuclear fission reactors, fission products are produced. Fissionproducts absorb neutrons. Normally, in the breeder reactor fuel cycle,reprocessed fuel that is relatively free of neutron absorbing fissionproducts is provided to the reactor core to generate heat that, in turn,is used to produce electricity. In this case, the fission products havebeen previously separated-out of the spent reactor fuel duringreprocessing that occurs before the reprocessed fuel can be provided tothe reactor core to produce the electricity. Therefore, it may bedesirable to separate fission products from the fuel before reprocessingbegins in order to more cost effectively reprocess the fuel.

An advanced gas-cooled nuclear fission reactor (AGR) uses a graphiteneutron moderator and a carbon dioxide (CO₂) coolant. AGRs obtain higherthermal efficiencies of about 40% and achieve higher burnups compared toPWRs and BWRs. The fuel is UO₂ pellets clad in stainless steel. Thecoolant is circulated through the reactor core and then passed through asteam generator outside the core, but still within the pressure vessel.Reactor control of the fission process is by means of control rods andreactor shutdown is achieved by means of nitrogen injection into thereactor core. Injection of balls comprising boron provides a redundantshutdown capability. Fission product production may have similar effectson fuel rod integrity, as previously mentioned for PWRs, BWRs and FNRs.Fission products produced during operation of the AGR includetechnetium-99, ruthenium-106, cesium-134 and cerium-144, neptunium-237and others.

There are other reactor designs under consideration in the nuclearindustry but are, however, not in wide use. These other reactor designsinclude a light water cooled graphite-moderated reactor (coolant isboiling water); pressurized heavy water reactor (heavy water moderator,unenriched uranium fuel); sodium-cooled thermal reactor (thermalneutrons and sodium coolant); advanced pressurized water reactor(passive safety systems); simplified boiling water reactor (naturalconvection and no circulation pumps), among others. However, regardlessof the reactor design, all nuclear fission reactors produce fissionproducts that may have deleterious effects.

Thus, ameliorating the presence of fission product solids and gases innuclear fuel rods for all reactor designs can help reduce risk of fuelrod swelling, cracking and rupture. Such amelioration may also reducepossible undesirable fission product gas and cladding chemicalinteraction which might lead to a breach of the cladding and release offission products into the primary coolant system. Various systems areknown in the art to prevent uncontrolled release of fission productsinto the primary coolant system. For example, fission products escapinginto the reactor coolant may be scrubbed therefrom by use of filters anddemineralizers.

A technique to remove fission gas from nuclear fuel is disclosed in U.S.Pat. No. 3,432,388, issued Mar. 11, 1969 in the name of Peter Fortescueand titled “Nuclear Reactor System With Fission Gas Removal.” Thispatent discloses a fluid-cooled nuclear reactor having a venting systemfor relieving pressure inside clad fuel pins. According to this patent,a passageway network interconnects the interiors of otherwise sealedclad fuel pins in different fuel elements, and gas is admitted theretoto initially bring the internal pressure to within a given increment ofthe coolant pressure at startup. When fission products cause theinternal pressure to increase, gas is vented to storage vessels tomaintain the internal pressure proportional to the coolant pressure.

Another technique to vent gaseous fission products is disclosed in U.S.Pat. No. 3,996,100 issued Dec. 7, 1976 in the names of Masaomi Oguma etal. and titled “Vented Nuclear Fuel Element.” This patent discloses avented nuclear fuel element that comprises a cladding tube containingnuclear fuel therein and a device disposed in the upper portion of thecladding tube for venting gaseous fission products released from thenuclear fuel. The venting device comprises a porous plug for closure ofthe top end of the venting tube, which plug has a property of gettingwet with the surrounding coolant, two plates that in cooperation withthe cladding tube define a chamber for holdup of the gaseous fissionproducts, a capillary tube for introducing the gaseous fission productsfrom the nuclear fuel into the upper portion of the chamber, anothercapillary tube for introducing the gaseous fission products from thelower portion of the chamber to the porous plug, and a check valve forpreventing the gaseous fission products within the chamber from flowingback into the interior of the cladding tube. Upon operation of thenuclear reactor, the gaseous fission products released from the nuclearfuel will pass through the check valve and the first mentioned capillarytube to reach the chamber, and from the chamber the gaseous fissionproducts will pass through the second mentioned capillary tube and bevented through the porous plug to the coolant surrounding the nuclearfuel element.

The foregoing examples of related art and limitations associatedtherewith are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification and a study of the drawings.

SUMMARY

The following embodiments and aspects thereof are described andillustrated in conjunction with nuclear fission reactors, vented nuclearfission fuel modules, methods, and vented nuclear fission fuel modulesystems which are meant to be illustrative, not limiting in scope. Invarious embodiments, one or more of the problems described above in theBackground have been reduced or eliminated, while other embodiments aredirected to other improvements.

Illustrative embodiments provide a nuclear fission reactor, a ventednuclear fission fuel module, methods therefore, and a vented nuclearfission fuel module system.

According to an aspect of this disclosure, there is provided a nuclearfission reactor, comprising: a nuclear fission fuel element capable ofgenerating a fission product; and means associated with the nuclearfission fuel element for controllably venting the fission product.

According to another aspect of the disclosure there is provided anuclear fission reactor, comprising: a nuclear fission fuel elementcapable of generating a gaseous fission product; a reactor vesselassociated with the nuclear fission fuel element for receiving thegaseous fission product; and means associated with the nuclear fissionfuel element for controllably venting the gaseous fission product intothe reactor vessel.

According to an additional aspect of the disclosure there is provided anuclear fission reactor, comprising: a nuclear fission fuel elementcapable of generating a gaseous fission product; a valve body associatedwith the nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product; and a valve inoperative communication with the plenum for controllably venting thegaseous fission product from the plenum.

According to a further aspect of the disclosure there is provided anuclear fission reactor, comprising: a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product; aplurality of valve bodies associated with respective ones of theplurality of nuclear fission fuel element bundles, at least one of theplurality of valve bodies defining a plenum therein for receiving thegaseous fission product; a valve disposed in the at least one of theplurality of valve bodies and in communication with the plenum forcontrollably venting the gaseous fission product from the plenum; aflexible diaphragm coupled to the valve for moving the valve; and aremovable cap threadably mounted on the valve.

According to still another aspect of the disclosure there is provided avented nuclear fission fuel module, comprising: a nuclear fission fuelelement capable of generating a fission product; and means associatedwith the nuclear fission fuel element for controllably venting thefission product.

According to yet another aspect of the disclosure there is provided avented nuclear fission fuel module, comprising: a nuclear fission fuelelement capable of generating a gaseous fission product; and meansassociated with the nuclear fission fuel element for controllablyventing the gaseous fission product.

According to another aspect of the disclosure there is provided a ventednuclear fission fuel module, comprising: a nuclear fission fuel elementcapable of generating a gaseous fission product; a valve body associatedwith the nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product; and a valve inoperative communication with the plenum for controllably venting thegaseous fission product from the plenum.

According to an additional aspect of the disclosure there is provided avented nuclear fission fuel module, comprising: a plurality of nuclearfission fuel element bundles capable of generating a gaseous fissionproduct; a plurality of valve bodies associated with respective ones ofthe plurality of nuclear fission fuel element bundles, at least one ofthe plurality of valve bodies defining a plenum therein for receivingthe gaseous fission product; a valve disposed in the at least one of theplurality of valve bodies and in communication with the plenum forcontrollably venting the gaseous fission product from the plenum; aflexible diaphragm coupled to the valve for moving the valve; and aremovable cap threadably mounted on the valve.

According to a further aspect of the disclosure there is provided avented nuclear fission fuel module system, comprising: a nuclear fissionfuel element capable of generating a fission product; and meansassociated with the nuclear fission fuel element for controllablyventing the fission product.

According to still another aspect of the disclosure there is provided avented nuclear fission fuel module system, comprising: a nuclear fissionfuel element capable of generating a gaseous fission product; and meansassociated with the nuclear fission fuel element for controllablyventing the gaseous fission product.

According to yet another aspect of the disclosure there is provided avented nuclear fission fuel module system, comprising: a nuclear fissionfuel element capable of generating a gaseous fission product; a valvebody associated with the nuclear fission fuel element, the valve bodydefining a plenum therein for receiving the gaseous fission product; anda valve in operative communication with the plenum for controllablyventing the gaseous fission product from the plenum.

According to another aspect of the disclosure there is provided a ventednuclear fission fuel module system, comprising: a plurality of nuclearfission fuel element bundles capable of generating a gaseous fissionproduct; a plurality of valve bodies associated with respective ones ofthe plurality of nuclear fission fuel element bundles, at least one ofthe plurality of valve bodies defining a plenum therein for receivingthe gaseous fission product; a valve disposed in the at least one of theplurality of valve bodies and in communication with the plenum forcontrollably venting the gaseous fission product from the plenum; aflexible diaphragm coupled to the valve for moving the valve; and aremovable cap threadably mounted on the valve.

According to an additional aspect of the disclosure there is provided amethod of operating a nuclear fission reactor, comprising: generating afission product by activating a nuclear fission fuel element; andcontrollably venting the fission product by operating venting meansassociated with the nuclear fission fuel element.

According to a further aspect of the disclosure there is provided amethod of operating a nuclear fission reactor, comprising: generating agaseous fission product by activating a nuclear fission fuel element;receiving the gaseous fission product into a reactor vessel coupled tothe nuclear fission fuel element; and operating venting means associatedwith the nuclear fission fuel element for controllably venting thegaseous fission product into the reactor vessel.

According to still another aspect of the disclosure there is provided amethod of operating a nuclear fission reactor, comprising: receiving agaseous fission product into a plenum defined by a valve body associatedwith a nuclear fission fuel element; and controllably venting thegaseous fission product from the plenum by operating means incommunication with the plenum for venting the gaseous fission productfrom the plenum.

According to yet another aspect of the disclosure there is provided amethod of operating a nuclear fission reactor, comprising: receiving agaseous fission product into a plenum defined by at least one of aplurality of valve bodies associated with respective ones of a pluralityof nuclear fission fuel element bundles; controllably venting thegaseous fission product from the plenum by operating a valve in the atleast one of the plurality of valve bodies, the valve being incommunication with the plenum; displacing the valve by allowing movementof a flexible diaphragm coupled to the valve; and threadably mounting acap on the valve.

According to another aspect of the disclosure there is provided a methodof assembling a vented nuclear fission fuel module, comprising:receiving a nuclear fission fuel element capable of generating a fissionproduct; and receiving means associated with the nuclear fission fuelelement for controllably venting the fission product.

According to an additional aspect of the disclosure there is provided amethod of assembling a vented nuclear fission fuel module, comprising:receiving a nuclear fission fuel element capable of generating a gaseousfission product; coupling means to the nuclear fission fuel element forcontrollably venting the gaseous fission product into a reactor vessel;and coupling means for collecting the gaseous fission product to theventing means.

According to a further aspect of the disclosure there is provided amethod of assembling a vented nuclear fission fuel module, comprising:receiving a nuclear fission fuel element capable of generating a gaseousfission product; coupling a valve body to the nuclear fission fuelelement, the valve body defining a plenum therein for receiving thegaseous fission product; and disposing a valve in communication with theplenum for controllably venting the gaseous fission product from theplenum.

According to still another aspect of the disclosure there is provided amethod of assembling a vented nuclear fission fuel module, comprising:receiving a plurality of nuclear fission fuel element bundles capable ofgenerating a gaseous fission product; coupling a valve body to at leastone of the plurality of nuclear fission fuel element bundles, the valvebody defining a plenum therein for receiving the gaseous fissionproduct; disposing a valve in the valve body and in communication withthe plenum for controllably venting the gaseous fission product from theplenum; coupling a flexible diaphragm to the valve for moving the valve;and threadably mounting a removable cap on the valve.

A feature of some embodiments and aspects of the present disclosure isthe provision of means associated with a nuclear fission fuel elementfor venting a fission product gas from the nuclear fission fuel element.

Another feature of some embodiments and aspects of the presentdisclosure is the provision of a valve body associated with the nuclearfission fuel element, the valve body defining a plenum therein and avalve in communication with the plenum.

Yet another feature of some embodiments and aspects of the disclosure isthe provision of a sensor in communication with the plenum for sensingfission product gas pressure in the plenum.

Yet another feature of some embodiments and aspects of the disclosure isthe provision of a sensor in communication with the plenum for sensingtype of fission product gas in the plenum.

A further feature of some embodiments and aspects of the disclosure isthe provision of a canister surrounding the nuclear fission fuelelement, the canister comprising a tube sheet therein having a contourshaped for guiding a coolant along a coolant flow path extending from afirst opening defined by the canister and through a second openingdefined by the canister.

An additional feature of some embodiments and aspects of the disclosureis the provision of a canister surrounding the nuclear fission fuelelement, the canister comprising a ceramic tube sheet therein fordissipating heat and having a contour shaped for guiding a coolant alonga coolant flow path extending from a first opening defined by thecanister and through a second opening defined by the canister.

In addition to the foregoing, various other method and/or device aspectsare set forth and described in the teachings such as text (e.g., claimsand/or detailed description) and/or drawings of the present disclosure.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE FIGURES

While the specification concludes with claims particularly pointing-outand distinctly claiming the subject matter of the present disclosure, itis believed the disclosure will be better understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings. In addition, the use of the same symbols in different drawingswill typically indicate similar or identical items.

FIG. 1 is a view in partial elevation of an illustrative pressurizedwater reactor (PWR) including a plurality of vented nuclear fission fuelmodules disposed therein;

FIG. 2 is a view in partial elevation of an illustrative boiling waterreactor (BWR) including the plurality of vented nuclear fission fuelmodules disposed therein;

FIG. 3 is view in partial elevation of an illustrative advancedgas-cooled reactor (AGR) including the plurality of vented nuclearfission fuel modules disposed therein;

FIG. 4 is view in partial elevation of an illustrative fast neutronreactor (FNR) including the plurality of vented nuclear fission fuelmodules disposed therein;

FIG. 5 is a view in transverse cross section of an illustrativecylindrically shaped nuclear fission reactor core including theplurality of vented nuclear fission fuel modules and a plurality ofcontrol rods disposed therein;

FIG. 6 is a view in transverse cross section of an illustrativehexagonally shaped nuclear fission reactor core including the pluralityof vented nuclear fission fuel modules and the plurality of control rodsdisposed therein;

FIG. 7 is a view in transverse cross section of an illustrativeparallelepiped shaped traveling wave fast neutron nuclear fissionreactor core including the plurality of vented nuclear fission fuelmodules and the plurality control rods disposed therein;

FIG. 8 is view in transverse cross section of an illustrativeparallelepiped shaped traveling wave fast neutron breeder nuclearfission reactor core including the plurality of vented nuclear fissionfuel modules and the plurality of control rods disposed therein;

FIG. 9 is a view in transverse cross section of an illustrativecylindrically shaped vented nuclear fission fuel canister having aplurality of nuclear fuel elements disposed therein;

FIG. 10 is a view in transverse cross section of an illustrativeparallelepiped shaped vented nuclear fission fuel canister having theplurality of nuclear fuel elements disposed therein;

FIG. 11 is a view in transverse cross section of an illustrativehexagonally shaped vented nuclear fission fuel canister having theplurality of nuclear fuel elements disposed therein;

FIG. 12 is an isometric view in vertical section of one of the pluralityof nuclear fission fuel elements;

FIG. 13 is a view in partial elevation of the plurality of ventednuclear fission fuel modules disposed on a reactor core lower supportplate;

FIG. 14 is a view taken along section line 14-14 of FIG. 13;

FIG. 15 is a fragmentary view in perspective of an exterior of one ofthe vented nuclear fission fuel modules;

FIG. 16 is a fragmentary view in perspective and partial verticalsection of the vented nuclear fission fuel module;

FIG. 17 is a view in elevation of an illustrative articulatedmanipulator arm in operable position to manipulate a cap belonging tothe vented nuclear fission fuel module;

FIG. 18 is a plan view of the articulated manipulator arm in operableposition to manipulate the cap belonging to the vented nuclear fissionfuel module;

FIG. 19 is a view in elevation of the articulated manipulator armoperating a ball valve belonging to the vented nuclear fission fuelmodule for releasing a gaseous fission product therefrom;

FIG. 20 is a fragmentary view in perspective and partial verticalsection of the vented nuclear fission fuel module including a sensordisposed therein, the sensor being coupled to a controller by means of aconduit (e.g., electrical or optical);

FIG. 21 is a fragmentary view in perspective and partial verticalsection of the vented nuclear fission fuel module including a sensordisposed therein, the sensor being coupled to a controller by means ofradio frequency transmission;

FIG. 22 is a fragmentary view in perspective and partial verticalsection of the vented nuclear fission fuel module including a reservoirfor collecting fission product gas;

FIG. 23 is a fragmentary view in perspective and partial verticalsection of the vented nuclear fission fuel module including a reservoirhaving a filter therein for separating and/or capturing a condensed(i.e., liquid or solid) fission product from the fission product gas;

FIG. 24 is a view in partial elevation of a suction device carried bythe articulated manipulator arm for suctioning the fission product gasfrom the vented nuclear fission fuel module;

FIGS. 25-72 are flowcharts of illustrative methods of operating anuclear fission reactor comprising a vented nuclear fission fuel module;and

FIGS. 73-120 are flow charts of illustrative methods of assembling thevented nuclear fission fuel module.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented herein.

In addition, the present application uses formal outline headings forclarity of presentation. However, it is to be understood that theoutline headings are for presentation purposes, and that different typesof subject matter may be discussed throughout the application (e.g.,device(s)/structure(s) may be described under process(es)/operationsheading(s) and/or process(es)/operations may be discussed understructure(s)/process(es) headings; and/or descriptions of single topicsmay span two or more topic headings). Hence, the use of the formaloutline headings is not intended to be in any way limiting.

Moreover, the herein described subject matter sometimes illustratesdifferent components contained within, or connected with, differentother components. It is to be understood that such depictedarchitectures are merely illustrative, and that in fact many otherarchitectures may be implemented which achieve the same functionality.In a conceptual sense, any arrangement of components to achieve the samefunctionality is effectively “associated” such that the desiredfunctionality is achieved. Hence, any two components herein combined toachieve a particular functionality can be seen as “associated with” eachother such that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected”, or“operably coupled,” to each other to achieve the desired functionality,and any two components capable of being so associated can also be viewedas being “operably couplable,” to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents, and/or wirelessly interactable, and/or wirelesslyinteracting components, and/or logically interacting, and/or logicallyinteractable components.

In some instances, one or more components may be referred to herein as“configured to,” “configurable to,” “operable/operative to,”“adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Thoseskilled in the art will recognize that “configured to” can generallyencompass active-state components and/or inactive-state componentsand/or standby-state components, unless context requires otherwise.

Therefore, referring to FIG. 1, there is shown a nuclear fission reactorand system, such as a pressurized water reactor (PWR) generally referredto as 10, which is configured to remove fission product gases.Pressurized water reactor 10 comprises a nuclear reactor core, generallyreferred to as 20, for generating heat due to nuclear fission. Housed inreactor core 20 are a plurality of vented nuclear fission fuel modules,generally referred to as 30 (only three of which are shown) for suitablyventing fission product gases, and which are described in detailhereinbelow. A plurality of longitudinally extending and longitudinallymovable control rods 35 are associated with respective ones of theplurality of vented nuclear fission fuel modules 30 for controlling thefission chain reaction occurring within vented nuclear fission fuelmodules 30. In other words, control rods 35 comprise a suitable neutronabsorber material having an acceptably high neutron absorptioncross-section that controls the fission chain reaction. In this regard,the absorber material may be a metal or metalloid selected from thegroup consisting essentially of lithium, silver, indium, cadmium, boron,cobalt, hafnium, dysprosium, gadolinium, samarium, erbium, europium andmixtures thereof. Alternatively, the absorber material may be a compoundor alloy selected from the group consisting essentially ofsilver-indium-cadmium, boron carbide, zirconium diboride, titaniumdiboride, hafnium diboride, gadolinium titanate, dysprosium titanate andmixtures thereof. Control rods 35 will controllably supply negativereactivity to reactor core 20. Thus, control rods 35 provide areactivity management capability to reactor core 20. In other words,control rods 35 are capable of controlling the neutron flux profileacross nuclear fission reactor core 20 and thus influence variousoperating characteristics of nuclear fission reactor core 20, includingfission product generation.

Referring again to FIG. 1, the plurality of vented nuclear fission fuelmodules 30 rest on a lower core support plate 40 for supporting ventednuclear fission fuel modules 30 thereon. Lower core support plate 40defines a bore 50 therethrough in communication with vented nuclearfission fuel modules 30 for providing coolant to vented nuclear fissionfuel modules 30, such as along fluid flow lines 60. The coolant isdistilled light water (H₂O). Reactor core 20 is disposed within areactor pressure vessel 70 for preventing leakage of radioactivematerials, including fission product gasses, solids or liquids fromreactor core 20 to the surrounding biosphere. Pressure vessel 70 may besteel, concrete or other material of suitable size and thickness toreduce risk of such radiation leakage and to support required pressureloads. In addition, there is a containment vessel 80 sealinglysurrounding parts of reactor 10 for added assurance that leakage ofradioactive materials, including fission product gasses, solids orliquids from reactor core 20 to the surrounding biosphere is prevented.

Still referring again to FIG. 1, a primary coolant loop comprises afirst primary loop pipe segment 90 that is coupled to reactor core 20for reasons disclosed momentarily. A pressurizer 100 is coupled toprimary loop pipe segment 90 for pressurizing the primary loop, whichpressurizer 100 includes a distilled first body of water 105 and apressurizer heater 107 for heating first body of water 105. First bodyof water 105 in pressurizer 100 is heated by pressurizer heater 107 tocreate a steam bubble above first body of water 105 that is inpressurizer 100. Pressurizer 100 provides an expansion space by means ofthe steam bubble to accommodate changes in water volume during operationof pressurized water reactor 10. Thus, pressure is controlled in theprimary coolant loop by increasing or decreasing the steam pressure inpressurizer 100. First primary loop pipe segment 90 extends from reactorcore 20 to an inlet plenum 115 defined by a heat exchanger or steamgenerator 110. Coolant flows through first primary loop pipe segment 90,into inlet plenum 115 and thereafter through a plurality of invertedU-shaped heat transfer tubes 120 (only one of which is shown) that arein communication with inlet plenum 115. Heat transfer tubes 120 aresupported by a horizontally oriented steam generator tube sheet 125 andmay be stabilized by a plurality of anti-vibration bars (not shown)connected to heat transfer tubes 120. An exit of each heat transfer tube120 is in communication with an outlet plenum 130 defined by steamgenerator 110, which outlet plenum 130 is in communication with a secondprimary loop pipe segment 140. Outlet plenum 130 is sealingly segregatedfrom inlet plenum 115 by a vertically oriented divider plate 135. Heattransfer tubes 120 are surrounded by a second body of water 150 having apredetermined temperature. The coolant fluid flowing through heattransfer tubes 120 will transfer its heat to second body of water 150,which is at a lower temperature than the fluid flowing through heattransfer tubes 120. As the fluid flowing through heat transfer tubes 120transfers its heat to second body of water 150, a portion of second bodyof water 150 will vaporize to steam 160 according to the predeterminedtemperature within steam generator 110. Steam 160 will then travelthrough a steam line 170 which has one end thereof in vaporcommunication with steam 160 and another end thereof in liquidcommunication with body of water 150. A rotatable turbine 180 is coupledto steam line 170, such that turbine 180 rotates as steam 160 passestherethrough. An electrical generator 190, which is coupled to turbine180, such as by a rotatable turbine shaft 200, generates electricity asturbine 180 rotates. In addition, a condenser 210 is coupled to steamline 170 and receives the steam passing through turbine 180. Condenser210 condenses the steam to liquid water and passes any waste heat, via arecirculation flow path 212 and an electro-mechanical first pump 214, toa heat sink, such as a cooling tower 220, which is associated withcondenser 210. The liquid water condensed by condenser 210 is pumpedalong steam line 170 from condenser 210 to steam generator 110 by meansof an electro-mechanical second pump 230 interposed between condenser210 and steam generator 110. It should be understood that steamgenerator 110, steam line 170, turbine 180, shaft 200, generator 190,condenser 210, cooling tower 220, first pump 214 and second pump 230define a secondary coolant loop separated from the previously mentionedprimary coolant loop.

Referring again to FIG. 1, a third electro-mechanical pump 240 iscoupled to a third primary loop pipe segment 250 for allowing a suitablecoolant to flow through reactor core 20 in order to cool reactor core20. First, second and third primary loop coolant pipe segments90/140/250, respectively, may be made from any suitable material, suchas stainless steel. It may be appreciated that, if desired, first,second and third primary loop coolant pipe segments 90/140/250 may bemade not only from ferrous alloys, but also from non-ferrous alloys,zirconium-based alloys or other suitable structural materials orcomposites. Third primary loop coolant pipe segment 250 opens onto adowncomer region 260 defined by a longitudinally extending annular panel270 disposed between vented nuclear fission fuel modules 30 and aninterior wall of reactor pressure vessel 70. Downcomer region 260 isshaped to guide coolant down the downcomer region 260 and into bore 50,so that the coolant can be directed to vented nuclear fission fuelmodules 30. Thus, it should be appreciated that pressurized waterreactor 10 comprises or includes vented nuclear fission fuel modules 30,which are described in detail hereinbelow.

Referring to FIG. 2, there is shown an alternative embodiment nuclearfission reactor and system, which is a boiling water reactor (BWR),generally referred to as 280, that is configured to remove fissionproduct gases. Boiling water reactor 280 comprises a nuclear reactorcore, generally referred to as 290, for generating heat due to nuclearfission. Housed in reactor core 290 are a plurality of the previouslymentioned vented nuclear fission fuel modules 30 (only three of whichare shown), which are described in detail hereinbelow. Vented nuclearfission fuel modules 30 are allowed to heat the coolant in reactor core290, such that steam 295 is produced in reactor core 290. A plurality ofthe previously mentioned longitudinally extending and longitudinallymovable control rods 35 are associated with respective ones of theplurality of vented nuclear fission fuel modules 30 for controlling thefission chain reaction occurring within vented nuclear fission fuelmodules 30. The plurality of vented nuclear fission fuel modules 30 reston lower core support plate 40 for supporting vented nuclear fissionfuel modules 30 thereon. Lower core support plate 40 defines bore 50therethrough that is in communication with vented nuclear fission fuelmodules 30 for providing coolant to vented nuclear fission fuel modules30, such as along fluid flow lines 300. Reactor core 290 is disposedwithin reactor pressure vessel 70 for preventing leakage of radioactivematerials, including fission product gasses, solids or liquids fromreactor core 290 to the surrounding biosphere. Pressure vessel 70 may besteel, concrete or other material of suitable size and thickness toreduce risk of such radiation leakage and to support required pressureloads, as in the case of the previously mention pressurized waterreactor 10. In addition, there is a containment vessel 80 sealinglysurrounding parts of reactor 280 for added assurance that leakage ofradioactive materials, including fission product gasses, solids orliquids from reactor core 290 to the surrounding biosphere is prevented.

Referring again to FIG. 2, a single coolant loop comprises a steam line310 that is coupled to reactor core 290 for reasons disclosedmomentarily. Rotatable turbine 180 is coupled to steam line 310, suchthat turbine 180 rotates as steam 160 passes therethrough. Electricalgenerator 190, which is coupled to turbine 180, such as by rotatableturbine shaft 200, generates electricity as turbine 180 rotates. Inaddition, condenser 210 is coupled to steam line 310 and receives thesteam passing through turbine 180. Condenser 210 condenses the steam toliquid water and passes any waste heat via recirculation fluid path 212and electro-mechanical first pump 214 to a heat sink, such as coolingtower 220, which is associated with condenser 210. The liquid watercondensed by condenser 210 is pumped along a coolant pipe 320 fromcondenser 210 to reactor pressure vessel 70 by means of anelectro-mechanical pump 330 interposed between condenser 210 and reactorpressure vessel 70. It should be understood that steam line 310, turbine180, shaft 200, generator 190, condenser 210, cooling tower 220, coolantpipe 320 and pump 330 define a coolant loop for circulating coolantthrough reactor core 290. It may be appreciated that, if desired, steamline 310 and coolant pipe 320 may be made from ferrous alloys (e.g.,stainless steel), non-ferrous alloys, zirconium-based alloys or othersuitable structural materials or composites. Thus, it should beappreciated that boiling water reactor 280 comprises or includes ventednuclear fission fuel modules 30, which are described in detailhereinbelow.

Referring to FIG. 3, there is shown another alternative embodimentnuclear fission reactor and system, which is an advanced gas-cooledreactor (AGR) generally referred to as 340, that is configured to removefission product gases. Advanced gas-cooled reactor 340 comprises anuclear reactor core, generally referred to as 350, for generating heatdue to nuclear fission. Housed in reactor core 350 are a plurality ofthe previously mentioned vented nuclear fission fuel modules 30 (onlytwo of which are shown), which are described in detail hereinbelow. Thecoolant used to cool nuclear fission fuel modules 30 may be carbondioxide (CO₂), which is circulated through reactor core 350 in a mannerdescribed hereinbelow. Neutrons produced by the fission chain reactionoccurring in reactor core 350 are moderated by a plurality of verticallyoriented graphite blocks 360 (only four of which are shown) disposedadjacent to respective ones of vented nuclear fission fuel modules 30. Aplurality of the previously mentioned longitudinally extending andlongitudinally movable control rods 35 are associated with respectiveones of the plurality of vented nuclear fission fuel modules 30 forcontrolling the fission chain reaction occurring within vented nuclearfission fuel modules 30. The plurality of vented nuclear fission fuelmodules 30 rest on lower core support plate 40 for supporting ventednuclear fission fuel modules 30 thereon. Lower core support plate 40defines bore 50 therethrough that is in communication with ventednuclear fission fuel modules 30 for providing coolant to vented nuclearfission fuel modules 30, such as along fluid flow lines 370. Reactorcore 350 is disposed within reactor pressure vessel 70 for preventingleakage of radioactive materials, including fission product gasses,solids or liquids from reactor core 350 to the surrounding biosphere. Asmentioned hereinabove, pressure vessel 70 may be steel, concrete orother material of suitable size and thickness to reduce risk of suchradiation leakage and to support required pressure loads, as in the caseof the previously mention pressurized water reactor 10. In addition,there is a containment vessel 80 sealingly surrounding parts of reactor340 for added assurance that leakage of radioactive materials, includingfission product gasses, solids or liquids from reactor core 350 to thesurrounding biosphere is prevented.

Referring again to FIG. 3, a primary coolant loop comprises a firstprimary loop pipe segment 380 that is coupled to reactor core 350 forreasons disclosed momentarily. First primary loop pipe segment 380extends from reactor core 350 to a heat exchanger or steam generator390. Coolant flows through first primary loop pipe segment 380, intosteam generator 390 and thereafter through a second primary loop pipesegment 400 that is coupled steam generator 390 at an end thereof and toa blower or recirculation fan 410 at another end thereof. Recirculationfan 410 is in fluid (i.e., gas) communication with reactor core 350.Recirculation fan 410 circulates the coolant through first primary looppipe segment 380, through steam generator 390, through second primaryloop pipe segment 400, into bore 50 that is formed in core lower supportplate 40, and into vented nuclear fission fuel modules 30 and across thesurfaces of graphite moderators 360, such as along fluid flow lines 370.The coolant then flows to steam generator 390. In this manner, heat dueto fission is transported away from reactor core 350.

Still referring to FIG. 3, steam generator 390 includes a secondary looppassing therethrough. The secondary loop comprises at least one heattransfer tube 430 partially filled by a body of water 440 having apredetermined temperature. The gas flowing across the exterior surfaceof heat transfer tube 430 will transfer its heat to body of water 440,which is at a lower temperature than the gas flowing across heattransfer tube 430. As the gas flowing across the exterior surface ofheat transfer tube 430 transfers its heat to body of water 440, aportion of body of water 440 will vaporize to steam 450 according to thepredetermined temperature within heat transfer tube 430. Steam 450 willthen travel through a steam line 460 due to pumping action of anelectro-mechanical pump 470 coupled to steam line 460. The previouslymentioned rotatable turbine 180 is coupled to steam line 460, such thatturbine 180 rotates as steam 450 passes therethrough. Previouslymentioned electrical generator 190, which is coupled to turbine 180,such as by rotatable turbine shaft 200, generates electricity as turbine180 rotates. In addition, condenser 210 is coupled to steam line 460 andreceives the steam passing through turbine 180. Condenser 210 condensesthe steam to liquid water and passes any waste heat via recirculationfluid path 212 and electro-mechanical first pump 214 to a heat sink,such as cooling tower 220, which is associated with condenser 210. Theliquid water condensed by condenser 210 is pumped along steam line 460from condenser 210 to body of water 440 by means of electro-mechanicalpump 470 that is interposed between condenser 210 and steam generator390. It should be understood that steam generator 390, steam line 460,turbine 180, shaft 200, generator 190, condenser 210, cooling tower 220and pump 470 define a secondary coolant loop that is separate from theprimary coolant loop. The primary coolant loop and the secondary coolantloop cooperate to carry heat away from nuclear fission fuel modules 30.Thus, it should be appreciated that advanced gas-cooled reactor 340comprises or includes vented nuclear fission fuel modules 30, which aredescribed in detail hereinbelow.

Referring to FIG. 4, there is shown yet another alternative embodimentnuclear fission reactor and system, such as a fast neutron nuclearfission reactor (FNR), generally referred to as 480, which is configuredto remove fission product gases. As described more fully presently,reactor 480 may be a traveling wave fast neutron nuclear fission reactor(TWR). In this regard, traveling wave nuclear fission reactor 480comprises a nuclear fission reactor core, generally referred to as 490,that includes vented nuclear fission fuel modules 30. Nuclear fissionreactor core 490 is housed within a reactor core enclosure 495 whichacts to maintain vertical coolant flow through the core. Enclosure 495may also function as a radiation shield to protect in-pool componentssuch as heat exchangers from neutron bombardment. Previously mentionedcontrol rods 35 longitudinally extend into nuclear fission reactor core490 for controlling the fission process occurring therein.

Referring again to FIG. 4, nuclear fission reactor core 490 is disposedwithin previously mentioned reactor pressure vessel 70. For reasonsprovided hereinbelow, pressure vessel 70 is substantially (e.g., about90%) filled with a pool of coolant 500, such as liquid sodium, to anextent that nuclear fission reactor core 490 is submerged in the pool ofcoolant. In addition, containment vessel 80 sealingly surrounds parts oftraveling wave nuclear fission reactor 480 for reasons previouslymentioned.

Still referring to FIG. 4, a primary loop coolant pipe 510 is coupled tonuclear fission reactor core 490 for allowing a suitable coolant to flowthrough nuclear fission reactor core 490 along a coolant flow stream orflow path 515 in order to cool nuclear fission reactor core 490. Primaryloop coolant pipe 510 may be made from stainless steel or fromnon-ferrous alloys, zirconium-based alloys or other suitable structuralmaterials or composites. The coolant carried by primary loop coolantpipe 510 may be a liquid metal selected from the group consistingessentially of sodium, potassium, lithium, lead and mixtures thereof. Onthe other hand, the coolant may be a metal alloy, such as lead-bismuth(Pb—Bi). Suitably, in an illustrative embodiment contemplated herein,the coolant is a liquid sodium (Na) metal or sodium metal mixture, suchas sodium-potassium (Na—K).

Referring yet again to FIG. 4, the heat-bearing coolant generated bynuclear fission reactor core 490 flows along flow path 515 to anintermediate heat exchanger 520 that is also submerged in coolant pool500. Intermediate heat exchanger 520 may be made from any convenientmaterial resistant to the heat and corrosive effects of the sodiumcoolant in coolant pool 500, such as stainless steel. The coolantflowing along coolant flow path 515 flows through intermediate heatexchanger 520 and continues through primary loop coolant pipe 510. Itmay be appreciated that the coolant leaving intermediate heat exchanger520 has been cooled due to the heat transfer occurring in intermediateheat exchanger 520, as disclosed more fully hereinbelow. A pump 530,which may be an electro-mechanical pump, is coupled to primary loop pipe510, and is in fluid communication with the reactor coolant carried byprimary loop coolant pipe 510, for pumping the reactor coolant throughprimary loop pipe 510, through reactor core 490, along coolant flow path515 and into intermediate heat exchanger 520.

Referring yet again to FIG. 4, a secondary loop pipe 540 is provided forremoving heat from intermediate heat exchanger 520. Secondary loop pipe540 comprises a secondary “hot” leg pipe segment 550 and a secondary“cold” leg pipe segment 560. Secondary hot leg pipe segment 550 andsecondary cold leg pipe segment 560 are integrally connected tointermediate heat exchanger 520. Secondary loop pipe 540, which includeshot leg pipe segment 550 and cold leg pipe segment 560, contains afluid, such as any one of the coolant choices previously mentioned.Secondary hot leg pipe segment 550 extends from intermediate heatexchanger 520 to a steam generator and superheater combination 570(hereinafter referred to as “steam generator 570”), for reasonsdescribed momentarily. In this regard, after passing through steamgenerator 570, the coolant flowing through secondary loop pipe 540 andexiting steam generator 570 is at a lower temperature and enthalpy thanbefore entering steam generator 570 due to the heat transfer occurringwithin steam generator 570. After passing through steam generator 570,the coolant is pumped, such as by means of another pump 580, which maybe an electro-mechanical pump, along “cold” leg pipe segment 560, whichextends into intermediate heat exchanger 520 for providing thepreviously mentioned heat transfer. The manner in which steam generator570 generates steam is generally described immediately hereinbelow.

Referring yet again to FIG. 4, disposed in steam generator 570 is a bodyof water 590 having a predetermined temperature. The fluid flowingthrough secondary hot leg pipe segment 550 will transfer its heat bymeans of conduction and convection to body of water 590, which is at alower temperature than the fluid flowing through secondary hot leg pipesegment 550. As the fluid flowing through secondary hot leg pipe segment550 transfers its heat to body of water 590, a portion of body of water590 will vaporize to steam 600 according to the predeterminedtemperature within steam generator 570. Steam 600 will then travelthrough a steam line 610, which steam line 610 has one end thereof invapor communication with steam 600 and another end thereof in liquidcommunication with body of water 590. Previously mentioned rotatableturbine 180 is coupled to steam line 610, such that turbine 180 rotatesas steam 600 passes therethrough. Electrical generator 190, which iscoupled to turbine 180 by rotatable turbine shaft 200, generateselectricity as turbine 180 rotates. In addition, previously mentionedcondenser 210 is coupled to steam line 610 and receives the steampassing through turbine 180. Condenser 210 condenses the steam to liquidwater and passes any waste heat via recirculation fluid path 212 andelectro-mechanical pump 214 to heat sink or cooling tower 220, which isassociated with condenser 210. The liquid water condensed by condenser210 is pumped along steam line 610 from condenser 210 to steam generator570 by means of yet another pump 620, which may be an electro-mechanicalpump, interposed between condenser 290 and steam generator 570.

Referring to FIGS. 5, 6, and 7, reactor cores 20/290/350/490 may obtainvarious configurations to accommodate vented nuclear fission fuelmodules 30. In this regard, any of nuclear fission reactor cores20/290/350/490 may be generally cylindrically shaped to obtain agenerally circular transverse cross section 630. Alternatively, any ofnuclear fission reactor cores 20/290/350/490 may be generallyhexagonally shaped to obtain a generally hexagonal transverse crosssection 640. As another alternative, any of nuclear fission reactorcores 20/290/350/490 may be generally parallepiped shaped to obtain agenerally rectangular transverse cross section 650. The generallyrectangular transverse cross section 650 has a first end 660 and asecond end 670 that is opposite first end 660, for reasons providedhereinbelow.

Referring to FIGS. 4 and 7, regardless of the configuration or shapeselected for the nuclear fission reactor cores, the nuclear fissionreactor core may be operated as a traveling wave nuclear fission reactorcore, if desired. For example, in the case of nuclear fission reactorcore 490, a nuclear fission igniter 680, which includes an isotopicenrichment of nuclear fissionable material, such as, without limitation,U-233, U-235 or Pu-239, is suitably located in nuclear fission reactorcore 490. By way of example only and not by way of limitation, igniter680 may be located near first end 660 that is opposite second end 670 ofnuclear fission reactor core 490. Neutrons are released by igniter 680.The neutrons that are released by igniter 680 are captured by fissileand/or fertile material within nuclear fission fuel module 30 toinitiate the previously mentioned nuclear fission chain reaction.Igniter 680 may be removed once the fission chain reaction becomesself-sustaining, if desired.

As best seen in FIG. 7, igniter 680 initiates a three-dimensional,traveling deflagration wave or “burn wave” 690. When igniter 680generates neutrons to cause “ignition”, burn wave 690 travels outwardlyfrom igniter 680 that is near first end 660 and toward second end 670 ofreactor core 490, so as to form the traveling or propagating burn wave690. Speed of the traveling burn wave 690 may be constant ornon-constant. Thus, the speed at which burn wave 690 propagates can becontrolled. For example, longitudinal movement of the previouslymentioned control rods 35 in a predetermined or programmed manner candrive down or lower neutronic reactivity of vented nuclear fission fuelmodules 30. In this manner, neutronic reactivity of nuclear fuel that ispresently being burned behind burn wave 690 or at the location of burnwave 690 is driven down or lowered relative to neutronic reactivity of“unburned” nuclear fuel ahead of burn wave 690. This result gives theburn wave propagation direction indicated by directional arrow 700.Controlling reactivity in this manner maximizes the propagation rate ofburn wave 690 subject to operating constraints for reactor core 490,such as amount of permissible fission product production and/or neutronfluence limitations of reactor core structural materials.

The basic principles of such a traveling wave nuclear fission reactorare disclosed in more detail in co-pending U.S. patent application Ser.No. 11/605,943 filed Nov. 28, 2006 in the names of Roderick A. Hyde, etal. and titled “Automated Nuclear Power Reactor For Long-TermOperation”, which application is assigned to the assignee of the presentapplication, the entire disclosure of which is hereby incorporated byreference.

Referring to FIG. 8, there is shown a fast neutron breeder reactor core,generally referred to as 710. Fast neutron breeder reactor core 710 issubstantially similar to fast neutron reactor core 490, except thatbreeder fuel modules 720 may be arranged as a “breeding blanket” aroundthe interior periphery or throughout the interior of nuclear fissionbreeder reactor core 710 for breeding nuclear fuel, as well known in theart of fast neutron breeder reactor design. In this regard, breeder fuelmodules 720 house fertile nuclear fuel that will transmute to fissilenuclear fuel. A further alternative is that breeder fission fuel modules720 and nuclear fission fuel modules 30 may comprise a predeterminedmixture of fertile and fissile nuclides.

Referring to FIGS. 9, 10, and 11, vented nuclear fission fuel module 30comprises an upright canister 730 for housing or surrounding a pluralityof bundled-together cylindrical fuel pins or fuel elements 740 that areactivated by a neutron source. It should be appreciated that nuclearfission fuel module 30 may also comprise a single fuel element 740.Canister 730 comprises a canister shell 735 that may be generallycylindrical having a circular transverse cross section, generallyreferred to as 742. Alternatively, canister shell 735 may have aparallepiped shape, such as a rectangle or square shape, generallyreferred to as 744. As another alternative, canister shell 735 may havea generally hexagonal shape having a hexagonal transverse cross section,generally referred to as 746. Thus, it may be appreciated that canister730, including canister shell 735, may obtain any suitable shaperequired by an operator of nuclear fission reactors 10, 280, 340 or 480.In any of the above mentioned embodiments, canister shell 735 may beused to provide structural support to the fuel elements therein or mayact to direct a flow of coolant. In some embodiments, the coolant may bedirected through openings in the canister shell, 735.

With particular reference to FIG. 12, each fuel element 740 comprises aplurality of nuclear fuel pellets 750 stacked end-to-end therein, whichnuclear fuel pellets 750 are housed in a cylindrical fuel rod claddingtube 760. Nuclear fuel pellets 750 are neutronically activated duringthe nuclear fission process, such as by an initial source of neutrons.Fuel rod cladding tube 760 has an open end 762 and a closed end 764. Inaddition, diameters of cladding 762 and fuel pellets 750 are sized suchthat a gap 770 is defined therebetween for escape of gaseous fissionproducts from nuclear fuel pellets 750, which gaseous fission productstravel into and upwardly through gap 770. Nuclear fuel pellets 750comprise the afore-mentioned fissile nuclide, such as uranium-235,uranium-233 or plutonium-239. Alternatively, nuclear fuel pellets 750may comprise a fertile nuclide, such as thorium-232 and/or uranium-238,which may be transmuted via neutron capture during the fission processinto the fissile nuclides mentioned immediately hereinabove. Suchfertile nuclide material may be housed in breeder rods (not shown)disposed in the previously mentioned breeder fuel modules 720. Nuclearfuel pellets 750 comprising fissile and/or fertile nuclear fuel willgenerate the fission products mentioned hereinabove.

In this regard, by way of example only and not by way of limitation, andstill referring to FIG. 12, nuclear fuel pellets 750 may be made from anoxide selected from the group consisting essentially of uranium monoxide(UO), uranium dioxide (UO₂), thorium dioxide (ThO₂) (also referred to asthorium oxide), uranium trioxide (UO₃), uranium oxide-plutonium oxide(UO—PuO), triuranium octoxide (U₃O₈) and mixtures thereof.Alternatively, nuclear fuel pellets 750 may substantially compriseuranium either alloyed or unalloyed with other metals, such as, but notlimited to, zirconium or thorium metal. As yet another alternative,nuclear fuel pellets 750 may substantially comprise a carbide of uranium(UC_(x)) or a carbide of thorium (ThC_(x)). For example, nuclear fuelpellets 750 may be made from a carbide selected from the groupconsisting essentially of uranium monocarbide (UC), uranium dicarbide(UC₂), uranium sesquicarbide (U₂C₃), thorium dicarbide (ThC₂), thoriumcarbide (ThC) and mixtures thereof. As another non-limiting example,nuclear fuel pellets 750 may be made from a nitride selected from thegroup consisting essentially of uranium nitride (U₃N₂), uraniumnitride-zirconium nitride (U₃N₂Zr₃N₄), uranium-plutonium nitride((U—Pu)N), thorium nitride (ThN), uranium-zirconium alloys(U_(x)Zr_(y)), and mixtures thereof. Fuel rod cladding material 760,which longitudinally surrounds the stack of nuclear fuel pellets 750,may be a suitable zirconium alloy, such as ZIRCOLOY™ (trademark of theWestinghouse Electric Corporation located in Pittsburgh, Pa., U.S.A.),which has known resistance to corrosion and cracking. Cladding tube 760may be made from other materials, as well, such as ferritic martensiticsteels.

Referring to FIGS. 13, 14, 15 and 16, the structure and operation ofvented nuclear fission fuel module 30 will now be described. Disposedwithin canister 730 and connected thereto, such as by welding orpress-fit, is a tube sheet 780 oriented transversely with respect to alongitudinal axis of canister 730. Tube sheet 780 having a plurality ofvertically oriented bores 790 for receiving respective ones of theplurality of cladding tubes 760 extending therethrough. It may beappreciated that, as cladding tubes 760 that belong to fuel elements 740extend through bores 790, fuel elements 740 may be affixed to tube sheet780 thereat, such as by a press-fit or welding. However, it should beappreciated that the coolant will not contact that portion of fuelelements 740 residing in bores 790. In other words, that portion of fuelelements 740 residing in bores 790 may tend to experience a higher thandesired temperature due to presence of tube sheet 780 surrounding theportion of fuel elements 740 residing in bores 790. That is, the coolantis blocked or prevented from reaching that portion of fuel elements 740residing in bores 790 due to presence of tube sheet 780. Blocking orpreventing coolant from reaching that portion of fuel elements 740residing in bores 790 creates higher temperatures at that region ofcladding 760. Such high temperatures may, in turn, compromise thestructural integrity of cladding 760. To solve this problem, tube sheet780 may be made from a silicon-carbon (SiC), alumina (Al₂O₃) or aluminumnitride (AlN) ceramic or ceramic composite material, if desired. Such amaterial is known to resist high temperatures, fracture and corrosion,and has low neutron absorption and superior heat dissipation capability.Alternatively, tube sheet 780 may be stainless steel or ZIRCALOY™. As analternative, fuel elements 740 may be formed so as to contain void ornon-fissionable material in the vicinity of tube sheet 780 so as not togenerate heat during reactor operation. Fuel elements may be supportedsuch that expansion of the elements in the axial direction due tothermal expansion or radiation induced expansion is permitted. Tubesheet 780 has a generally arcuate-shaped surface 800 extending around anunderside of tube sheet 780, for reasons presented hereinbelow. Inaddition, open ends 762 of fuel elements 740 suitably extend above tubesheet 780 for reasons provided hereinbelow.

Referring again to FIGS. 13, 14, 15 and 16, canister 730 defines aplenum volume 810 above tube sheet 780, for reasons provided presently.Plenum volume 810 includes a lower plenum portion 812. Canister 730further comprises a valve body 820 associated with fuel elements 740.Valve body 820 comprises a riser portion 830 integrally connected tocanister shell 735, the riser portion 830 defining an upper plenumportion 835 that is in intimate communication with lower plenum portion812. Riser portion 830 has external threads surrounding an exteriorsurface thereof for reasons provided hereinbelow. Open ends 762 of fuelelements 740 are exposed to plenum volume 810 such that gaseous fissionproducts rising through gap 770 of fuel element 740 are received inplenum volume 810 and collected therein.

Referring yet again to FIGS. 13, 14, 15 and 16, a flexible or resilientdisk-shaped diaphragm 840 is interposed between lower plenum portion 812and upper plenum portion 835. Diaphragm 840 defines a plurality ofapertures 850 therethrough for allowing the gaseous fission products totravel from lower plenum portion 812 to upper plenum portion 835.Diaphragm 840 may be made from any suitable resilient material resistantto heat, corrosion and radiation effects. By way of example only, andnot by way of limitation, diaphragm 840 may be made from a NEOPRENE®(i.e., chloroprene rubber) material, which is a registered trademark ofDupontDow, Incorporated, located in Wilmington, Del., U.S.A. Diaphragm840 may also be made from a butyl rubber material. As another example,diaphragm 840 may be made from “spring steel”, which is a carbon steelalloy having high yield strength. Spring steel returns to its originalshape after bending. Valve body 820 also defines a vent opening 860 incommunication with upper plenum portion 835 for allowing the fissionproduct gas to exit or vent from vented nuclear fission module 30 alonggas flow path 865 and into the surrounding coolant (see FIG. 19).

Still referring to FIGS. 13, 14, 15 and 16, a ball 870 is disposed inupper plenum portion 835 and rests on resilient diaphragm 840. Ball 870is aligned with vent opening 860 and resides between vent opening 860and resilient diaphragm 840. In this manner, ball 870 is in operativecondition to block, obstruct and otherwise close-off vent opening 860when gaseous fission products are not being vented from vented nuclearfission fuel module 30. Ball 870 may be made from any suitable materialresistant to heat and corrosion, such as stainless steel or ZIRCALOY™.Mounted on riser portion 830 is a cap 880 having internal threads forthreadably engaging the external threads surrounding riser portion 830.Cap 880 protects riser portion 830 during handling of vented nuclearfission fuel module 30 and also precludes inadvertent venting of gaseousfission products should ball 870 not perfectly block vent opening 860due to manufacturing imperfections. Moreover, this ball valve may beoperable to controllably vent the gaseous fission product according to apredetermined periodic release rate for minimizing size of an associatedgaseous fission product clean-up system.

Referring to FIGS. 13 and 14, canister shell 735 has a plurality of flowopenings 890 defined by a bottom portion thereof for allowing coolantthat flows along flow paths 60, 300, 370 or 515 to enter canister shell735. The coolant entering canister shell 735 will flow upwardly thereinand contact arcuate-shaped surface 800. The contour of arcuate-shapedsurface 800 guides the coolant out a plurality of flow ports 900 definedby a side portion of canister shell 735, in order to flow along coolantflow path 905.

With particular reference to FIGS. 17 and 18, a manipulator, generallyreferred to as rethreading, is provided for unthreading cap 880 fromriser portion 830 and for rethreading cap 880 onto riser portion 830. Inthis regard, manipulator 910 comprises a remotely operable articulatedmanipulator arm 920. Manipulator arm 920 comprises a first component 930rotatable about first axis 935 in the direction of double-headed arrow937. Manipulator arm 920 further comprises a second component 940rotatable about a second axis 945 in the direction of double-headedarrow 947. In addition, manipulator arm 920 comprises a third component950 rotatable about a third axis 955 in the direction of double-headedarrow 957. Further, manipulator arm 920 comprises a fourth component 960rotatable about a fourth axis 965 in the direction of double headedarrow 967. Moreover, manipulator arm 920 further comprises a fifthcomponent 970 rotatable about a fifth axis 975 in the direction ofdouble-headed arrows 977. A handler or gripper 980 is rotatably coupledto fifth component 970, so as to be rotatable about a sixth axis 985, inthe direction of double-headed arrows 987. Gripper 980 is capable ofopening and closing in order to grip and unthread cap 880 from riserportion 830 of canister shell 735 and rethread cap 880 onto riserportion 830 of canister shell 735. A plurality of servo-motors 990a/b/c/d are electrically or pneumatically coupled to respective ones ofcomponents 930/940/950/960/970 and gripper 980 for operating components930/940/950/960/970 and gripper 980. Components 930/940/950/960/970 andgripper 980 are selectively operable, such as by means of a controller1000 electrically or pneumatically coupled to servo-motors 990 a/b/c/d.Manipulator arm 920 may be a robotic device, such as may be availablefrom ABB Automation Technologies AB—Robotics, located in Vasterds,Sweden. Controller 1000 and associated software may be of a type thatmay be available from ABB Automation Technologies AB—Robotics.

As best seen in FIG. 19, gripper 980 is capable of holding a plunger orspike 1010 that is used to depress or downwardly translate ball 870 bycontact therewith. Bail 870 is allowed to downwardly translate byelastic deflection of resilient diaphragm 840 which supports ball 870.Passageway 860 will then become unobstructed to allow the gaseousfission products to escape through passageway 860, such as along flowlines represented by arrow 865. As passageway 860 becomes unobstructed,the gaseous fission product will escape nuclear fission fuel module 30and flow into the surrounding coolant. When spike 1010 is removed, ball870 will return to its initial position to block or obstruct passageway860 due to an upward contact force exerted by resilient diaphragm 840 asresilient diaphragm 840 returns to its initial position. Thus,manipulator arm 920 cooperates with ball 870 and resilient diaphragm 840to controllably vent the gaseous fission product from nuclear fissionfuel module 30.

Referring to FIG. 20, a sensor or detector 1020 may be disposed in upperplenum portion 835 for detecting presence of gaseous fission productstherein. Detector 1020 may be a commercially available pressure detectorcapable of detecting pressure of any gaseous fission product in upperplenum portion 835, such as a N-E111 or N-E13 pressure transmitter thatmay be available from Ultra Electronics, Nuclear Sensors and ProcessInstrumentation, Incorporated located in Round Rock, Tex., U.S.A.Detecting fission gas pressure in upper plenum portion 835 will confirmthat a sufficient amount of fission gas is present in upper plenumportion 835, such that the fission gas should be out-gassed or relieved.Alternatively, detector 1020 may be a commercially availableradionuclide detector capable of detecting presence of a predeterminedradionuclide that is characteristic of a particular gaseous fissionproduct. Such a detector may be a gamma radiation detector of a typethat may be available from Fluke Biomedical, Incorporated, located inEverett, Wash., U.S.A. Alternatively, such a detector may be a chemicalsensor of a type that may be available from Pacific Northwest NationalLaboratory, Environmental Technology Division, located in Richland,Wash., U.S.A. Such a chemical sensor would sense certain types offission products in the gaseous fission product. As another alternative,such a detector may be a commercially available optical sensor fordetecting amount and/or type of gaseous fission product by means oflight wavelength associated with the amount and/or type of gaseousfission product. In this regard, such a detector may comprise a gasoptical spectrometer, which may be part of a suitable controller, suchas a controller and power supply combination 1030. Any of the detectorsmentioned hereinabove may comprise a signal carrier, such as anelectrical signal carrier (e.g., electrically conducting wire) forcarrying an electrical signal from the detector to a commerciallyavailable measuring device that detects and measures the amount and/ortype of gaseous fission product. Such a commercially available measuringdevice may be a component of controller and power supply combination1030. As an alternative, the signal carrier may be an optical fiber whendetector 1020 is an optical sensor or detector. In any event, controllerand power supply combination 1030 may be coupled to detector 1020, suchas by means of a conduit 1040 (e.g., electrical or optical), forsupplying power to detector 1020 and/or for receiving a gaseous fissionproduct detection signal from detector 1020. Detector 1020 may becalibrated only to transmit a detection signal when a threshold pressureor threshold quantity of gaseous fission products are present in upperplenum portion 835 because pressure and quantity of gaseous fissionproducts may be de minimis at reactor startup as compared to middle ofreactor life or end of reactor life. In some other embodiments, forexample, upper plenum portion 835 of vented nuclear fission fuel module30 may contain a mechanism that automatically raises and lowers ball 870in response to pressure and/or type of gaseous fission products detectedby detector 1020. A power supply would continuously supply electricalpower to the mechanism and detector 1020. Controller 1030 wouldinterpret the signal generated by detector 1020 to decide when to raiseand lower ball 870. In this manner, the manipulator 910 may beeliminated.

Referring to FIG. 21, a transmitter 1050 may be disposed in upper plenumportion 835 for transmitting information containing the pressure of, ormerely the presence of, a gaseous fission product in upper plenumportion 835. Transmitter 1050 may be calibrated such that thetransmission signal also identifies the particular canister 730 causingtransmitter 1050 to transmit its signal. A radio frequency receiver 1060is provided for receiving the transmission signal and for logginginformation about which canister 730 is transmitting the signal, so thatthe particular canister 730 is selectively degassed by manipulator 910.Transmitter 1050 is configured to transmit a signal from sensor ordetector 1020. Transmitter 1050 may comprise a radio frequencytransmitter. Thus, transmitter 1050 may be configured to transmit anidentification signal identifying canister 730 and the associated valvebody 820.

Referring to FIG. 22, there is shown yet another embodiment of ventednuclear fission fuel module 30. In this embodiment, controller 1030,conduit 1040 and detector 1020 are coupled to canister 730, aspreviously described. In addition, a fan (not shown) or a pump 1070 hasa suction side in communication with upper plenum portion 835, such asby means of a first tube 1080. A discharge side of pump 1070 is incommunication with a fission gas reservoir 1090, such as by means of asecond tube 1100. Fission gas reservoir 1090 is capable of sealablyisolating the gaseous fission product therein and may remain in situ ortransported off-site for waste disposal. Fission gas reservoir 1090 maybe coupled to or decoupled from pump 1070, such as by means of a coupler1102. In a sense, fission gas reservoir 1090 is capable of being coupledto and decoupled from reactor vessel 70 itself because fission gasreservoir 1090 is at least initially disposed in reactor vessel 70. Pump1070 is coupled to controller 1030, such as by a wire 1105, so that pump1070 is operated in response to pressure of, or mere presence of,gaseous fission products detected by detector 1020 that is disposed inupper plenum portion 835. Thus, pump 1070 may be operated periodicallydepending on the amount of gaseous fission products that may accumulateagain in upper plenum portion 835 after periodic venting. Alternatively,pump 1070 may be operated continuously regardless of the amount ofgaseous fission products in upper plenum portion 835. This alternativeembodiment allows vented nuclear fission fuel module 30 to removesubstantially all (i.e., about 98%) of gaseous fission products thatwould otherwise accumulate in the reactor coolant system. Removal of thegaseous fission products separates (i.e., “takes out”) the gaseousfission products from neutronic communication with the reactor coolantsystem.

Referring to FIG. 23, there is shown another embodiment vented nuclearfission fuel module 30. This embodiment is substantially similar to theembodiment illustrated in FIG. 22, except that a fission product filter1110 is provided in reservoir 1090 to segregate and/or capture fissionproduct solids and liquids from the gaseous fission products. In otherwords, fission product filter 1110 separates a condensed phase fissionproduct from the gaseous fission product. In this regard, fissionproduct filter 1110 may be made from suitable activated alumina,activated carbon or zeolite (i.e., aluminosilicate). Alternatively,fission product filter 1110 may be a filter meeting the standards of theHealth and Environmental Protection Act (HEPA) of the U.S.A. or a “coldtrap”. In this regard, the HEPA filter may comprise shredded fillermaterial of glass fiber/acrylic binder, plastics/rubber and aluminum. Asanother alternative, fission product filter 1110 may be a permeable orsemi-permeable membrane. By way of example only, and not by way oflimitation, such a permeable or semi-permeable membrane may be made ofany suitable material known in the art, have a thickness of betweenapproximately 5 to approximately 10 millimeters and may have a pore sizeof between approximately 100 to approximately 1,000 angstroms. Asanother alternative, fission product filter 1110 may comprise anysuitable commercially available electrostatic collector. On the otherhand, fission product filter 1110 may be a “cold trap”. A cold trapproduces nucleation sites for gathering and retaining impurities from afluid in order to clean the fluid. In this regard, the fluid to becleaned is fed into a tank (e.g., reservoir 1090) where the temperatureof the fluid is reduced. As the temperature decreases, impurities insolution reach saturation. Further cooling produces supersaturation.This causes impurities to nucleate and precipitate at nucleation sitesin the cold trap. The purified fluid is caused to then leave the tank.In addition, nucleation and precipitation can be enhanced by presence ofa wire mesh, if desired. Regardless of the form of fission productfilter 1110, fission product filter 1110 may be removable from reservoir1090 for off-site disposal of the fission products separated andcaptured thereby. An exit conduit 1112 having a backflow preventionvalve 1114 therein may be provided for exit of gas that is free offission products. Backflow prevention valve 1114 prevents eitherbackflow of the fission product-free gas or backflow of coolant intoreservoir 1090.

Referring to FIG. 24, there is shown another embodiment vented nuclearfission fuel module 30. This embodiment is substantially similar to theembodiment illustrated in FIG. 22, except that a suction device 1120that is carried by articulated manipulator arm 920 is mounted on valvebody 820 so as to sealingly cover vent opening 860. Ball 870 isdepressed by spike 1010 in the manner previously mentioned to releasethe fission product gas. Pump 1070 is operated to draw the fissionproduct gas from suction device 1120, along a tube 1130 and intoreservoir 1090.

Illustrative Methods

Illustrative methods associated with illustrative embodiments of anuclear fission reactor and vented nuclear fission fuel module will nowbe described.

Referring to FIGS. 25-72, illustrative methods are provided foroperating a nuclear fission reactor.

Turning now to FIG. 25, an illustrative method 1140 of operating anuclear fission reactor starts at a block 1150. At a block 1160, themethod comprises generating a fission product by activating a nuclearfission fuel element. At a block 1170 the fission product iscontrollably vented by operating venting means associated with thenuclear fission fuel element. The method stops at a block 1180.

In FIG. 26, an illustrative method 1190 of operating a nuclear fissionreactor starts at a block 1200. At a block 1210, the method comprisesgenerating a gaseous fission product by activating a nuclear fissionfuel element. At a block 1220, the gaseous fission product is receivedinto a reactor vessel coupled to the nuclear fission fuel element. At ablock 1230, venting means associated with the nuclear fission fuelelement is operated for controllably venting the gaseous fission productinto the reactor vessel. The method stops at a block 1240.

In FIG. 26A, an illustrative method 1250 of operating a nuclear fissionreactor starts at a block 1260. At a block 1270, the method comprisesgenerating a gaseous fission product by activating a nuclear fissionfuel element. At a block 1280, the gaseous fission product is receivedinto a reactor vessel coupled to the nuclear fission fuel element. At ablock 1290, venting means associated with the nuclear fission fuelelement is operated for controllably venting the gaseous fission productinto the reactor vessel. At a block 1300, the gaseous fission productvented into the reactor vessel is collected by operating a gaseousfission product collecting means coupled to the venting means. Themethod stops at a block 1310.

In FIG. 26B, an illustrative method 1320 of operating a nuclear fissionreactor starts at a block 1330. At a block 1340, the method comprisesgenerating a gaseous fission product by activating a nuclear fissionfuel element. At a block 1350, the gaseous fission product is receivedinto a reactor vessel coupled to the nuclear fission fuel element. At ablock 1360, venting means associated with the nuclear fission fuelelement is operated for controllably venting the gaseous fission productinto the reactor vessel. At a block 1370, the gaseous fission productvented into the reactor vessel is collected by operating a gaseousfission product collecting means coupled to the venting means. At ablock 1380, the gaseous fission product vented into the reactor vesselis collected by operating a gaseous fission product collecting meanscapable of being coupled to the reactor vessel and thereafter capable ofbeing decoupled from the reactor vessel for removing the gaseous fissionproduct from the reactor vessel. The method stops at a block 1390.

In FIG. 26C, an illustrative method 1400 of operating a nuclear fissionreactor starts at a block 1402. At a block 1404, the method comprisesgenerating a gaseous fission product by activating a nuclear fissionfuel element. At a block 1406, the gaseous fission product is receivedinto a reactor vessel coupled to the nuclear fission fuel element. At ablock 1408, venting means associated with the nuclear fission fuelelement is operated for controllably venting the gaseous fission productinto the reactor vessel. At a block 1410, the gaseous fission productvented into the reactor vessel is collected by operating a gaseousfission product collecting means coupled to the venting means. At ablock 1412, the gaseous fission product vented into the reactor vesselis collected by operating a gaseous fission product collecting meanscapable of being coupled to the reactor vessel and thereafter capable ofremaining coupled to the reactor vessel for storing the gaseous fissionproduct at the reactor vessel. The method stops at a block 1414.

In FIG. 26D, an illustrative method 1416 of operating a nuclear fissionreactor starts at a block 1418. At a block 1420, the method comprisesgenerating a gaseous fission product by activating a nuclear fissionfuel element. At a block 1422, the gaseous fission product is receivedinto a reactor vessel coupled to the nuclear fission fuel element. At ablock 1424, venting means associated with the nuclear fission fuelelement is operated for controllably venting the gaseous fission productinto the reactor vessel. At a block a 1426, a coolant system inoperative communication with the venting means is provided for receivingthe gaseous fission product vented by the venting means. The methodstops at a block 1440.

In FIG. 26E, an illustrative method 1450 of operating a nuclear fissionreactor starts at a block 1460. At a block 1470, the method comprisesgenerating a gaseous fission product by activating a nuclear fissionfuel element. At a block 1480, the gaseous fission product is receivedinto a reactor vessel coupled to the nuclear fission fuel element. At ablock 1490, venting means associated with the nuclear fission fuelelement is operated for controllably venting the gaseous fission productinto the reactor vessel. At a block 1500, a coolant system in operativecommunication with the venting means is provided for receiving thegaseous fission product vented by the venting means. At a block 1510, aremoval system in operative communication with the coolant system isprovided for removing the gaseous fission product from the coolantsystem. The method stops at a block 1560.

In FIG. 26F, an illustrative method 1570 of operating a nuclear fissionreactor starts at a block 1580. At a block 1590, the method comprisesgenerating a gaseous fission product by activating a nuclear fissionfuel element. At a block 1600, the gaseous fission product is receivedinto a reactor vessel coupled to the nuclear fission fuel element. At ablock 1610, venting means associated with the nuclear fission fuelelement is operated for controllably venting the gaseous fission productinto the reactor vessel. At a block 1620, reclosable venting meansassociated with the nuclear fission fuel element is operated. The methodstops at a block 1630.

In FIG. 26G, an illustrative method 1640 of operating a nuclear fissionreactor starts at a block 1650. At a block 1660, the method comprisesgenerating a gaseous fission product by activating a nuclear fissionfuel element. At a block 1670, the gaseous fission product is receivedinto a reactor vessel coupled to the nuclear fission fuel element. At ablock 1680, venting means associated with the nuclear fission fuelelement is operated for controllably venting the gaseous fission productinto the reactor vessel. At a block 1690, sealably reclosable ventingmeans associated with the nuclear fission fuel element is operated. Themethod stops at a block 1700.

In FIG. 27, an illustrative method 1710 of operating a nuclear fissionreactor starts at a block 1720. At a block 1730, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 1740,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. The method stops at a block 1750.

In FIG. 28, an illustrative method 1760 of operating a nuclear fissionreactor starts at a block 1770. At a block 1780, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 1790,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 1800, the nuclear fissionfuel element is activated to generate the gaseous fission product. Themethod stops at a block 1810.

In FIG. 28A, an illustrative method 1820 of operating a nuclear fissionreactor starts at a block 1830. At a block 1840, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 1850,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 1860, a valve is operated.The method stops at a block 1870.

In FIG. 28B, an illustrative method 1880 of operating a nuclear fissionreactor starts at a block 1890. At a block 1900, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 1910,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 1920, a valve is operated.At a block 1930, movement of a flexible diaphragm coupled to the valveis allowed. The method stops at a block 1940.

In FIG. 29, an illustrative method 1950 of operating a nuclear fissionreactor starts at a block 1960. At a block 1970, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 1980 thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 1990, a valve is operated.At a block 2000 a cap is mounted on the valve. At a block 2010 amanipulator is extended to the cap for manipulating the cap. The methodstops at a block 2020.

In FIG. 30, an illustrative method 2030 of operating a nuclear fissionreactor starts at a block 2040. At a block 2050, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 2060,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2070, a valve is operated.At a block 2080, a manipulator is extended to the valve for manipulatingthe valve. The method stops at a block 2090.

In FIG. 30A, an illustrative method 2100 of operating a nuclear fissionreactor starts at a block 2110. At a block 2120, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 2130,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2140, an articulatedmanipulator arm is extended to the plenum. At a block 2150, a receptacleis carried on the articulated manipulator arm, the receptacle beingengageable with the plenum for receiving the gaseous fission productcontrollably vented from the plenum. The method stops at a block 2160.

In FIG. 31, an illustrative method 2170 of operating a nuclear fissionreactor starts at a block 2180. At a block 2190, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 2200,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2210, an articulatedmanipulator arm is extended to the plenum. At a block 2220, a receptacleis carried on the articulated manipulator arm, the receptacle beingengageable with the plenum for receiving the gaseous fission productcontrollably vented from the plenum. At a block 2230, a suction deviceis carried on the articulated manipulator arm. The method stops at ablock 2240.

In FIG. 31A, an illustrative method 2250 of operating a nuclear fissionreactor starts at a block 2260. At a block 2270, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 2280,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2290, the gaseous fissionproduct is controllably vented from the plenum by operating a valveresponsive to a pressure in the plenum. The method stops at a block2300.

In FIG. 31B, an illustrative method 2310 of operating a nuclear fissionreactor starts at a block 2320. At a block 2330, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element. At a block 2340,the gaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2350, the gaseous fissionproduct is controllably vented from the plenum by operating a valveresponsive to a type of gaseous fission product in the plenum. Themethod stops at a block 2360.

In FIG. 32, an illustrative method 2370 of operating a nuclear fissionreactor starts at a block 2380. At a block 2390, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2400, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2410, a sensor is disposedinto operative communication with the plenum. The method stops at ablock 2420.

In FIG. 33, an illustrative method 2430 of operating a nuclear fissionreactor starts at a block 2440. At a block 2450, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2460, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2470, a sensor is disposedinto operative communication with the plenum. At a block 2480, a sensoris disposed for sensing pressure in the plenum. The method stops at ablock 2490.

In FIG. 34, an illustrative method 2500 of operating a nuclear fissionreactor starts at a block 2510. At a block 2520, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2530, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2540, a sensor is disposedinto operative communication with the plenum. At a block 2550, a sensoris disposed for sensing a type of gaseous fission product in the plenum.The method stops at a block 2560.

In FIG. 34A, an illustrative method 2570 of operating a nuclear fissionreactor starts at a block 2580. At a block 2590, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2600, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2610, a sensor is disposedin the plenum. At a block 2620, a sensor is disposed for sensing aradioactive fission product in the plenum. The method stops at a block2630.

In FIG. 34B, an illustrative method 2640 of operating a nuclear fissionreactor starts at a block 2650. At a block 2660, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2670, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2680, a sensor is disposedin the plenum. At a block 2690, a radiation sensor is disposed. Themethod stops at a block 2700.

In FIG. 34C, an illustrative method 2710 of operating a nuclear fissionreactor starts at a block 2720. At a block 2730, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2740, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2750, a sensor is disposedin the plenum. At a block 2760, a chemical sensor is disposed. Themethod stops at a block 2770.

In FIG. 34D, an illustrative method 2780 of operating a nuclear fissionreactor starts at a block 2790. At a block 2800, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2810, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2820, a sensor is disposedin the plenum. At a block 2830, an optical sensor is disposed. Themethod stops at a block 2840.

In FIG. 34E, an illustrative method 2850 of operating a nuclear fissionreactor starts at a block 2860. At a block 2870, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2880, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2890, a sensor is disposedinto operative communication with the plenum. At a block 2900, atransmitter is disposed. The method stops at a block 2910.

In FIG. 35, an illustrative method 2920 of operating a nuclear fissionreactor starts at a block 2930. At a block 2940, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 2950, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 2960, a sensor is disposedinto operative communication with the plenum. At a block 2965, atransmitter is disposed. At a block 2970, a radio frequency transmitteris disposed. The method stops at a block 2980.

In FIG. 36, an illustrative method 2990 of operating a nuclear fissionreactor starts at a block 3000. At a block 3010, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3020, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3030, a sensor is disposedinto operative communication with the plenum. At a block 3035, atransmitter is disposed. At a block 3040, a transmitter is disposed thatis configured to transmit a signal from the sensor. The method stops ata block 3050.

In FIG. 37, an illustrative method 3060 of operating a nuclear fissionreactor starts at a block 3070. At a block 3080, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3090, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3100, a sensor is disposedinto operative communication with the plenum. At a block 3105, atransmitter is disposed. At a block 3110, a transmitter is disposed fortransmitting an identification signal identifying the valve body. Themethod stops at a block 3120.

In FIG. 37A, an illustrative method 3130 of operating a nuclear fissionreactor starts at a block 3140. At a block 3150, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3160, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3170, a sensor is disposedinto operative communication with the plenum. At a block 3175, atransmitter is disposed. At a block 3180, an electrical signal carrieris disposed. The method stops at a block 3190.

In FIG. 37B, an illustrative method 3191 of operating a nuclear fissionreactor starts at a block 3192. At a block 3193, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3194, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3195, a sensor is disposedinto operative communication with the plenum. At a block 3196, atransmitter is disposed. At a block 3197, an optical fiber is disposed.The method stops at a block 3198.

In FIG. 38, an illustrative method 3200 of operating a nuclear fissionreactor starts at a block 3210. At a block 3220, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3230, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3240, a valve is operated.At a block 3250, a vented nuclear fission fuel module is defined byinterconnecting the nuclear fission fuel element, the valve body and thevalve. The method stops at a block 3260.

In FIG. 39, an illustrative method 3270 of operating a nuclear fissionreactor starts at a block 3280. At a block 3290, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3300, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3305, a valve is operated.At a block 3310, a vented nuclear fission fuel module is defined byinterconnecting the nuclear fission fuel element, the valve body and thevalve. At a block 3320, the vented nuclear fission fuel module isdisposed in a thermal neutron reactor core. The method stops at a block3340.

In FIG. 40, an illustrative method 3350 of operating a nuclear fissionreactor starts at a block 3360. At a block 3370, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3380, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3385, a valve is operated.At a block 3390, a vented nuclear fission fuel module is defined byinterconnecting the nuclear fission fuel element, the valve body and thevalve. At a block 3400, the vented nuclear fission fuel module isdisposed in a fast neutron reactor core. The method stops at a block3410.

In FIG. 41, an illustrative method 3420 of operating a nuclear fissionreactor starts at a block 3421. At a block 3422, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3423, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3424, a valve is operated.At a block 3425, a vented nuclear fission fuel module is defined byinterconnecting the nuclear fission fuel element, the valve body and thevalve. At a block 3426, the vented nuclear fission fuel module isdisposed in a fast neutron breeder reactor core. The method stops at ablock 3427.

In FIG. 42, an illustrative method 3430 of operating a nuclear fissionreactor starts at a block 3431. At a block 3432, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3433, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3434, a valve is operated.At a block 3435, a vented nuclear fission fuel module is defined byinterconnecting the nuclear fission fuel element, the valve body and thevalve. At a block 3436, the vented nuclear fission fuel module isdisposed in a traveling wave fast neutron reactor core. The method stopsat a block 3437.

In FIG. 43, an illustrative method 3460 of operating a nuclear fissionreactor starts at a block 3470. At a block 3480, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3490, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3500, a canister surroundingthe fuel element is provided. The method stops at a block 3510.

In FIG. 44, an illustrative method 3520 of operating a nuclear fissionreactor starts at a block 3530. At a block 3540, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3550, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3560, a canister surroundingthe fuel element is provided. At a block 3570 a canister having a bottomportion defining a first opening is provided. At a block 3580, acanister having a side portion defining a second opening is provided.The method stops at a block 3590.

In FIG. 44A, an illustrative method 3600 of operating a nuclear fissionreactor starts at a block 3610. At a block 3620, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3630, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3640, a canister surroundingthe fuel element is provided. At a block 3650 a canister having a bottomportion defining a first opening is provided. At a block 3660, acanister having a side portion defining a second opening is provided. Ata block 3670, a canister is provided including a tube sheet thereinhaving a contour shaped for guiding a coolant along a coolant flow pathextending from the first opening and through the second opening. Themethod stops at a block 3680.

In FIG. 44B, an illustrative method 3690 of operating a nuclear fissionreactor starts at a block 3700. At a block 3710, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3720, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3730, a canister surroundingthe fuel element is provided. At a block 3740, a canister having abottom portion defining a first opening is provided. At a block 3750, acanister having a side portion defining a second opening is provided. Ata block 3760, a canister is provided including a ceramic tube sheettherein for dissipating heat and having a contour shaped for guiding acoolant along a coolant flow path extending from the first opening andthrough the second opening. The method stops at a block 3770.

In FIG. 45, an illustrative method 3780 of operating a nuclear fissionreactor starts at a block 3790. At a block 3800, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3810, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3820, the gaseous fissionproduct is received into a reservoir coupled to the venting means. Themethod stops at a block 3830.

In FIG. 46, an illustrative method 3840 of operating a nuclear fissionreactor starts at a block 3850. At a block 3860, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3870, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3880, the gaseous fissionproduct is received into a reservoir coupled to the venting means. At ablock 3890, a condensed phase fission product is separated from thegaseous fission product by passing the gaseous fission product through afilter. The method stops at a block 3900.

In FIG. 46A, an illustrative method 3910 of operating a nuclear fissionreactor starts at a block 3920. At a block 3930, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 3940, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 3950, the gaseous fissionproduct is received into a reservoir coupled to the venting means. At ablock 3960, a condensed phase fission product is separated from thegaseous fission product by passing the gaseous fission product through afilter. At a block 3970, a condensed phase fission product is separatedfrom the gaseous fission product by passing the gaseous fission productthrough a HEPA filter. The method stops at a block 3980.

In FIG. 46B, an illustrative method 3990 of operating a nuclear fissionreactor starts at a block 4000. At a block 4010, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4020, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4030, the gaseous fissionproduct is received into a reservoir coupled to the venting means. At ablock 4040, a condensed phase fission product is separated from thegaseous fission product by passing the gaseous fission product through afilter. At a block 4050, a condensed phase fission product is separatedfrom the gaseous fission product by passing the gaseous fission productthrough a semi-permeable membrane. The method stops at a block 4060.

In FIG. 46C, an illustrative method 4070 of operating a nuclear fissionreactor starts at a block 4080. At a block 4090, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4100, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4110, the gaseous fissionproduct is received into a reservoir coupled to the venting means. At ablock 4120, a condensed phase fission product is separated from thegaseous fission product by passing the gaseous fission product through afilter. At a block 4130, a condensed phase fission product is separatedfrom the gaseous fission product by passing the gaseous fission productthrough an electrostatic collector. The method stops at a block 4140.

In FIG. 46D, an illustrative method 4150 of operating a nuclear fissionreactor starts at a block 4160. At a block 4170, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4180, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4190, the gaseous fissionproduct is received into a reservoir coupled to the venting means. At ablock 4200, a condensed phase fission product is separated from thegaseous fission product by passing the gaseous fission product through afilter. At a block 4210, a condensed phase fission product is separatedfrom the gaseous fission product by passing the gaseous fission productthrough a cold trap. The method stops at a block 4220.

In FIG. 46E, an illustrative method 4230 of operating a nuclear fissionreactor starts at a block 4240. At a block 4250, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4260, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4270, the gaseous fissionproduct is received into a reservoir coupled to the valve. At a block4280, the gaseous fission product is received into a reservoir capableof being decoupled from the reactor vessel for removing the gaseousfission product from the reactor vessel. The method stops at a block4290.

In FIG. 46F, an illustrative method 4300 of operating a nuclear fissionreactor starts at a block 4310. At a block 4320, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4330, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4340, the gaseous fissionproduct is received into a reservoir coupled to the reactor vessel, thegaseous fission product being vented by the reactor vessel. At a block4350, the gaseous fission product is received into a reservoir capableof remaining coupled to the valve for storing the gaseous fissionproduct at the reactor vessel. The method stops at a block 4360.

In FIG. 46G, an illustrative method 4370 of operating a nuclear fissionreactor starts at a block 4380. At a block 4390, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4400, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4410, a coolant system isprovided in operative communication with the venting means for receivingthe gaseous fission product controllably vented by the venting means.The method stops at a block 4420.

In FIG. 46H, an illustrative method 4430 of operating a nuclear fissionreactor starts at a block 4440. At a block 4450, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4460, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4470, a coolant system isprovided in operative communication with the venting means for receivingthe gaseous fission product controllably vented by the venting means. Ata block 4480, a removal system is provided in operative communicationwith the coolant system for removing the gaseous fission product fromthe coolant system. The method stops at a block 4490.

In FIG. 46I, an illustrative method 4500 of operating a nuclear fissionreactor starts at a block 4510. At a block 4520, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4530, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4540, a reclosable ventingmeans is operated. The method stops at a block 4550.

In FIG. 46J, an illustrative method 4560 of operating a nuclear fissionreactor starts at a block 4570. At a block 4580, the method comprisesreceiving a gaseous fission product into a plenum defined by a valvebody associated with a nuclear fission fuel element, the valve bodycapable of being disposed in a reactor vessel. At a block 4590, thegaseous fission product is controllably vented from the plenum byoperating means in communication with the plenum for venting the gaseousfission product from the plenum. At a block 4600, a sealably reclosableventing means is operated. The method stops at a block 4610.

In FIG. 47, an illustrative method 4620 of operating a nuclear fissionreactor starts 4630. 4640, the method comprises receiving a gaseousfission product into a plenum defined by a valve body associated with anuclear fission fuel element, the valve body capable of being disposedin a reactor vessel. 4650, the gaseous fission product is controllablyvented from the plenum by operating means in communication with theplenum for venting the gaseous fission product from the plenum. At ablock 4660, operation of the venting means is controlled by operating acontroller coupled to the venting means. The method stops at a block4670.

In FIG. 48, an illustrative method 4680 of operating a nuclear fissionreactor starts at a block 4690. At a block 4700, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 4710, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 4720, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 4730, a cap is threadably mounted on the valve.The method stops at a block 4740.

In FIG. 48A, an illustrative method 4750 of operating a nuclear fissionreactor starts at a block 4760. At a block 4770, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 4780, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 4790, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 4880, a flexible diaphragm is coupled to thevalve for moving the valve to a closed position. At a block 4800, a capis threadably mounted on the valve. At a block 4810, a plurality ofnuclear fission fuel element bundles associated with respective ones ofthe plurality of valve bodies are activated, at least one of theplurality of nuclear fission fuel element bundles being capable ofgenerating the gaseous fission product. The method stops at a block4820.

In FIG. 48B, an illustrative method 4830 of operating a nuclear fissionreactor starts at a block 4840. At a block 4850, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 4860, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 4870, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 4890, a cap is threadably mounted on the valve.At a block 4900, movement of a flexible diaphragm capable of displacingthe valve to a closed position is allowed. The method stops at a block4910.

In FIG. 49, an illustrative method 4920 of operating a nuclear fissionreactor starts at a block 4930. At a block 4940, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 4950, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 4960, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 4980, a cap is threadably mounted on the valve.At a block 4990, an articulated manipulator arm is extended to the capfor threadably dismounting the cap from the valve. The method stops at ablock 5000.

In FIG. 50, an illustrative method 5010 of operating a nuclear fissionreactor starts at a block 5020. At a block 5030, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5040, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5050, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5070, a cap is threadably mounted on the valve.At a block 5080, an articulated manipulator arm is extended to the valvefor operating the valve. The method stops at a block 5090.

In FIG. 50A, an illustrative method 5100 of operating a nuclear fissionreactor starts at a block 5110. At a block 5120, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5130, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5140, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5160, a cap is threadably mounted on the valve.At a block 5170, an articulated manipulator arm is extended to theplenum. At a block 5180, a receptacle is carried on the articulatedmanipulator arm, the receptacle being engageable with the plenum forreceiving the gaseous fission product controllably vented from theplenum. The method stops at a block 5190.

In FIG. 51, an illustrative method 5200 of operating a nuclear fissionreactor starts at a block 5210. At a block 5220, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5230, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5240, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5260, a cap is threadably mounted on the valve.At a block 5270, an articulated manipulator arm is extended to theplenum. At a block 5280, a receptacle is carried on the articulatedmanipulator arm, the receptacle being engageable with the plenum forreceiving the gaseous fission product controllably vented from theplenum. At a block 5290, a suction device is carried. The method stopsat a block 5300.

In FIG. 52, an illustrative method 5310 of operating a nuclear fissionreactor starts at a block 5320. At a block 5330, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5340, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5350, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5370, a cap is threadably mounted on the valve.At a block 5380, a valve responsive to a pressure in the plenum isoperated. The method stops at a block 5390.

In FIG. 53, an illustrative method 5400 of operating a nuclear fissionreactor starts at a block 5410. At a block 5420, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5430, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5440, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5460, a cap is threadably mounted on the valve.At a block 5470, a valve responsive to a type of gaseous fission productin the plenum is operated. The method stops at a block 5480.

In FIG. 54, an illustrative method 5490 of operating a nuclear fissionreactor starts at a block 5500. At a block 5510, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5520, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5530, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5550, a cap is threadably mounted on the valve.At a block 5560, a sensor is disposed into operative communication withthe plenum. The method stops at a block 5570.

In FIG. 55, an illustrative method 5580 of operating a nuclear fissionreactor starts at a block 5590. At a block 5600, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5610, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5620, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5640, a cap is threadably mounted on the valve.At a block 5650, a sensor is disposed into operative communication withthe plenum. At a block 5660, a sensor is disposed for sensing a pressurein the plenum. The method stops at a block 5670.

In FIG. 56, an illustrative method 5680 of operating a nuclear fissionreactor starts at a block 5690. At a block 5700, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5710, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5720, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5740, a cap is threadably mounted on the valve.At a block 5750, a sensor is disposed into operative communication withthe plenum. At a block 5760, a sensor is disposed for sensing a type ofgaseous fission product in the plenum. The method stops at a block 5770.

In FIG. 56A, an illustrative method 5780 of operating a nuclear fissionreactor starts at a block 5790. At a block 5800, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5810, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5820, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5840, a cap is threadably mounted on the valve.At a block 5850, a sensor is disposed into operative communication withthe plenum. At a block 5860, a sensor is disposed for sensing aradioactive fission product in the plenum. The method stops at a block5870.

In FIG. 56B, an illustrative method 5880 of operating a nuclear fissionreactor starts at a block 5890. At a block 5900, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 5910, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 5920, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 5940, a cap is threadably mounted on the valve.At a block 5950, a sensor is disposed into operative communication withthe plenum. At a block 5960, a radiation sensor is disposed. The methodstops at a block 5970.

In FIG. 56C, an illustrative method 5980 of operating a nuclear fissionreactor starts at a block 5990. At a block 6000, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6010, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6020, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6040, a cap is threadably mounted on the valve.At a block 6050, a sensor is disposed into operative communication withthe plenum. At a block 6060, a chemical sensor is disposed. The methodstops at a block 6070.

In FIG. 56D, an illustrative method 6080 of operating a nuclear fissionreactor starts at a block 6090. At a block 6100, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6110, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6120, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6140, a cap is threadably mounted on the valve.At a block 6150, a sensor is disposed into operative communication withthe plenum. At a block 6160, an optical sensor is disposed. The methodstops at a block 6170.

In FIG. 56E, an illustrative method 6180 of operating a nuclear fissionreactor starts at a block 6190. At a block 6200, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6210, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6220, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6240, a cap is threadably mounted on the valve.At a block 6250, a sensor is disposed into operative communication withthe plenum. At a block 6260, a transmitter is disposed. The method stopsat a block 6270.

In FIG. 57, an illustrative method 6280 of operating a nuclear fissionreactor starts at a block 6290. At a block 6300, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6310, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6320, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6340, a cap is threadably mounted on the valve.At a block 6350, a sensor is disposed into operative communication withthe plenum. At a block 6355, a transmitter is disposed. At a block 6360,a radio frequency transmitter is disposed. The method stops at a block6370.

In FIG. 58, an illustrative method 6380 of operating a nuclear fissionreactor starts at a block 6390. At a block 6400, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6410, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6420, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6440, a cap is threadably mounted on the valve.At a block 6450, a sensor is disposed into operative communication withthe plenum. At a block 6455, a transmitter is disposed. At a block 6460,a transmitter is disposed that is configured to transmit a signal fromthe sensor. The method stops at a block 6470.

In FIG. 59, an illustrative method 6480 of operating a nuclear fissionreactor starts at a block 6490. At a block 6500, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6510, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6520, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6540, a cap is threadably mounted on the valve.At a block 6550, a sensor is disposed into operative communication withthe plenum. At a block 6555, a transmitter is disposed. At a block 6560,a transmitter is disposed that is configured to transmit anidentification signal identifying the valve body. The method stops at ablock 6570.

In FIG. 59A, an illustrative method 6580 of operating a nuclear fissionreactor starts at a block 6590. At a block 6600, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6610, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6620, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6640, a cap is threadably mounted on the valve.At a block 6650, a sensor is disposed into operative communication withthe plenum. At a block 6655, a transmitter is disposed. At a block 6660,an electrical signal carrier is disposed. The method stops at a block6670.

In FIG. 59B, an illustrative method 6671 of operating a nuclear fissionreactor starts at a block 6672. At a block 6673, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6674, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6675, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6676, a cap is threadably mounted on the valve.At a block 6677, a sensor is disposed into operative communication withthe plenum. At a block 6678, a transmitter is disposed. At a block 6679,an electrical signal carrier is disposed. The method stops at a block6680.

In FIG. 59C, an illustrative method 6681 of operating a nuclear fissionreactor starts at a block 6690. At a block 6700, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6710, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6720, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6740, a cap is threadably mounted on the valve.At a block 6750, a vented nuclear fission fuel module is defined byinterconnecting one of the plurality of nuclear fission fuel elementbundles, the valve body, the valve, the diaphragm and the removable cap.The method stops at a block 6760.

In FIG. 60, an illustrative method 6770 of operating a nuclear fissionreactor starts at a block 6780. At a block 6790, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6800, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 6810, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 6830, a cap is threadably mounted on the valve.At a block 6840, a vented nuclear fission fuel module is defined byinterconnecting one of the plurality of nuclear fission fuel elementbundles, the valve body, the valve, the diaphragm and the removable cap.At a block 6850, the vented nuclear fission fuel module is disposed in athermal neutron reactor core. The method stops at a block 6860.

In FIG. 61, an illustrative method 6870 of operating a nuclear fissionreactor starts at a block 6880. At a block 6890, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 6900, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7000, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7020, a cap is threadably mounted on the valve.At a block 7030, a vented nuclear fission fuel module is defined byinterconnecting one of the plurality of nuclear fission fuel elementbundles, the valve body, the valve, the diaphragm and the removable cap.At a block 7040, the vented nuclear fission fuel module is disposed in afast neutron reactor core. The method stops at a block 7050.

In FIG. 62, an illustrative method 7060 of operating a nuclear fissionreactor starts at a block 7070. At a block 7080, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7090, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7100, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7120, a cap is threadably mounted on the valve.At a block 7130, a vented nuclear fission fuel module is defined byinterconnecting one of the plurality of nuclear fission fuel elementbundles, the valve body, the valve, the diaphragm and the removable cap.At a block 7140, the vented nuclear fission fuel module is disposed in afast neutron breeder reactor core. The method stops at a block 7150.

In FIG. 63, an illustrative method 7160 of operating a nuclear fissionreactor starts at a block 7170. At a block 7180, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7190, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7200, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7220, a cap is threadably mounted on the valve.At a block 7230, a vented nuclear fission fuel module is defined byinterconnecting one of the plurality of nuclear fission fuel elementbundles, the valve body, the valve, the diaphragm and the removable cap.At a block 7240, the vented nuclear fission fuel module is disposed in atraveling wave fast neutron reactor core. The method stops at a block7250.

In FIG. 64, an illustrative method 7260 of operating a nuclear fissionreactor starts at a block 7270. At a block 7280, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7290, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7300, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7320, a cap is threadably mounted on the valve.At a block 7330, a canister surrounding at least one of the plurality ofnuclear fission fuel element bundles is provided. The method stops at ablock 7340.

In FIG. 65, an illustrative method 7350 of operating a nuclear fissionreactor starts at a block 7360. At a block 7370, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7380, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7390, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7410, a cap is threadably mounted on the valve.At a block 7420, a canister surrounding at least one of the plurality ofnuclear fission fuel element bundles is provided. At a block 7440, acanister having a bottom portion defining a flow opening is provided. Ata block 7440, a canister having a side portion defining a flow port isprovided. The method stops at a block 7450.

In FIG. 66, an illustrative method 7460 of operating a nuclear fissionreactor starts at a block 7470. At a block 7480, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7490, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7500, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7520, a cap is threadably mounted on the valve.At a block 7530, a canister surrounding at least one of the plurality ofnuclear fission fuel element bundles is provided. At a block 7540, acanister having a bottom portion defining a flow opening is provided. Ata block 7550, a canister having a side portion defining a flow port isprovided. At a block 7560, a canister is provided including a tube sheettherein having a contour on an underside surface thereof shaped forguiding a coolant along a coolant flow path extending from the flowopening and through the flow port. The method stops at a block 7570.

In FIG. 67, an illustrative method 7580 of operating a nuclear fissionreactor starts at a block 7590. At a block 7600, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7610, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7620, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7640, a cap is threadably mounted on the valve.At a block 7650, a canister surrounding at least one of the plurality ofnuclear fission fuel element bundles is provided. At a block 7660, acanister having a bottom portion defining a flow opening is provided. Ata block 7670, a canister having a side portion defining a flow port isprovided. At a block 7680, a canister is provided including a ceramictube sheet therein having a contour on an underside surface thereofshaped for guiding a coolant along a coolant flow path extending fromthe flow opening and through the flow port. The method stops at a block7690.

In FIG. 68, an illustrative method 7700 of operating a nuclear fissionreactor starts at a block 7710. At a block 7720, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7730, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7740, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7760, a cap is threadably mounted on the valve.At a block 7770, the gaseous fission product is received into areservoir coupled to the valve, the gaseous fission product being ventedby the valve. The method stops at a block 7780.

In FIG. 69, an illustrative method 7790 of operating a nuclear fissionreactor starts at a block 7800. At a block 7810, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7820, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7830, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7850, a cap is threadably mounted on the valve.At a block 7860, the gaseous fission product is received into areservoir coupled to the valve, the gaseous fission product being ventedby the valve. At a block 7870, a condensed phase fission product isseparated from the gaseous fission product by passing the gaseousfission product through a filter disposed in the reservoir. The methodstops at a block 7880.

In FIG. 70, an illustrative method 7890 of operating a nuclear fissionreactor starts at a block 7900. At a block 7910, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 7920, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 7930, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 7950, a cap is threadably mounted on the valve.At a block 7960, the gaseous fission product is received into areservoir coupled to the valve, the gaseous fission product being ventedby the valve. At a block 7970, a condensed phase fission product isseparated from the gaseous fission product by passing the gaseousfission product through a filter disposed in the reservoir. At a block7980, a condensed phase fission product is separated from the gaseousfission product by passing the gaseous fission product through a HEPAfilter. The method stops at a block 7990.

In FIG. 70A, an illustrative method 8000 of operating a nuclear fissionreactor starts at a block 8010. At a block 8020, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8030, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8040, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8060, a cap is threadably mounted on the valve.At a block 8070, the gaseous fission product is received into areservoir coupled to the valve, the gaseous fission product being ventedby the valve. At a block 8080, a condensed phase fission product isseparated from the gaseous fission product by passing the gaseousfission product through a filter disposed in the reservoir. At a block8090, a condensed phase fission product is separated from the gaseousfission product by passing the gaseous fission product through asemi-permeable membrane. The method stops at a block 8100.

In FIG. 70B, an illustrative method 8110 of operating a nuclear fissionreactor starts at a block 8120. At a block 8130, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8140, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8150, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8170, a cap is threadably mounted on the valve.At a block 8180, the gaseous fission product is received into areservoir coupled to the valve, the gaseous fission product being ventedby the valve. At a block 8190, a condensed phase fission product isseparated from the gaseous fission product by passing the gaseousfission product through a filter disposed in the reservoir. At a block8200, a condensed phase fission product is separated from the gaseousfission product by passing the gaseous fission product through anelectrostatic collector. The method stops at a block 8210.

In FIG. 70C, an illustrative method 8220 of operating a nuclear fissionreactor starts at a block 8230. At a block 8240, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8250, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8260, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8280, a cap is threadably mounted on the valve.At a block 8290, the gaseous fission product is received into areservoir coupled to the valve, the gaseous fission product being ventedby the valve. At a block 8300, a condensed phase fission product isseparated from the gaseous fission product by passing the gaseousfission product through a filter disposed in the reservoir. At a block8310, a condensed phase fission product is separated from the gaseousfission product by passing the gaseous fission product through coldtrap. The method stops at a block 8320.

In FIG. 70D, an illustrative method 8330 of operating a nuclear fissionreactor starts at a block 8340. At a block 8350, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8360, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8370, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8390, a cap is threadably mounted on the valve.At a block 8400, the gaseous fission product is received into areservoir coupled to the valve, the gaseous fission product being ventedby the valve. At a block 8410, the gaseous fission product is receivedinto a reservoir coupled to a reactor vessel. At a block 8420, thegaseous fission product is received into a reservoir capable of beingdecoupled from the reactor vessel for removing the gaseous fissionproduct from the reactor vessel. The method stops at a block 8430.

In FIG. 70E, an illustrative method 8440 of operating a nuclear fissionreactor starts at a block 8450. At a block 8460, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8470, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8480, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8500, a cap is threadably mounted on the valve.At a block 8510, the gaseous fission product is received into areservoir coupled to the valve, the gaseous fission product being ventedby the valve. At a block 8520, the gaseous fission product is receivedinto a reservoir coupled to a reactor vessel. At a block 8530, thegaseous fission product is received into a reservoir capable ofremaining coupled to the reactor vessel for storing the gaseous fissionproduct at the reactor vessel. The method stops at a block 8540.

In FIG. 70F, an illustrative method 8550 of operating a nuclear fissionreactor starts at a block 8560. At a block 8570, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8580, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8590, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8610, a cap is threadably mounted on the valve.At a block 8620, a coolant system is disposed in operative communicationwith the valve for receiving the gaseous fission product controllablyvented by the valve. The method stops at a block 8630.

In FIG. 70G, an illustrative method 8640 of operating a nuclear fissionreactor starts at a block 8650. At a block 8660, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8670, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8680, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8700, a cap is threadably mounted on the valve.At a block 8710, a coolant system is disposed in operative communicationwith the valve for receiving the gaseous fission product controllablyvented by the valve. At a block 8720, a removal system is disposed inoperative communication with the coolant system for removing the gaseousfission product from the coolant system. The method stops at a block8730.

In FIG. 70H, an illustrative method 8740 of operating a nuclear fissionreactor starts at a block 8750. At a block 8760, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8770, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8780, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8800, a cap is threadably mounted on the valve.At a block 8810, a reclosable valve is operated. The method stops at ablock 8820.

In FIG. 70I, an illustrative method 8830 of operating a nuclear fissionreactor starts at a block 8840. At a block 8850, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8860, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8870, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8890, a cap is threadably mounted on the valve.At a block 8900, a sealably reclosable valve is operated. The methodstops at a block 8910.

In FIG. 71, an illustrative method 8920 of operating a nuclear fissionreactor starts at a block 8930. At a block 8940, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 8950, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 8960, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 8980, a cap is threadably mounted on the valve.At a block 8990, the valve is operated to controllably vent the gaseousfission product according to a predetermined release rate for minimizingsize of an associated gaseous fission product clean-up system. Themethod stops at a block 9000.

In FIG. 72, an illustrative method 9010 of operating a nuclear fissionreactor starts at a block 9020. At a block 9030, the method comprisesreceiving a gaseous fission product into a plenum defined by at leastone of a plurality of valve bodies associated with respective ones of aplurality of nuclear fission fuel element bundles. At a block 9040, thegaseous fission product is controllably vented from the plenum byoperating a valve in the at least one of the plurality of valve bodies,the valve being in communication with the plenum. At a block 9050, thevalve is displaced by allowing movement of a flexible diaphragm coupledto the valve. At a block 9070, a cap is threadably mounted on the valve.At a block 9080, the valve is operated by operating a controller coupledto the valve. The method stops at a block 9090.

Referring to FIGS. 73-120, illustrative methods are provided forassembling a vented nuclear fission fuel module.

Turning now to FIG. 73, an illustrative method 9100 of assembling avented nuclear fission fuel module starts at a block 9110. At a block9120, the method comprises receiving a nuclear fission fuel elementcapable of generating a fission product. At a block 9130, meansassociated with the nuclear fission fuel element for controllablyventing the fission product is received. The method stops at a block9140.

In FIG. 74, an illustrative method 9150 of assembling a vented nuclearfission fuel module starts at a block 9160. At a block 9170, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9180, means is coupled to thenuclear fission fuel element for controllably venting the gaseousfission product into a reactor vessel. At a block 9190, means forcollecting the gaseous fission product is coupled to the venting means.The method stops at a block 9200.

In FIG. 75, an illustrative method 9210 of assembling a vented nuclearfission fuel module starts at a block 9220. At a block 9230, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9240, means is coupled to thenuclear fission fuel element for controllably venting the gaseousfission product into a reactor vessel. At a block 9250, means forcollecting the gaseous fission product is coupled to the venting means.At a block 9260, reclosable venting means is coupled to the nuclearfission fuel element for controllably venting the gaseous fissionproduct. The method stops at a block 9270.

In FIG. 76, an illustrative method 9280 of assembling a vented nuclearfission fuel module starts at a block 9290. At a block 9300, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9310, means is coupled to thenuclear fission fuel element for controllably venting the gaseousfission product into a reactor vessel. At a block 9320, means forcollecting the gaseous fission product is coupled to the venting means.At a block 9330, sealably reclosable venting means is coupled to thenuclear fission fuel element for controllably venting the gaseousfission product. The method stops at a block 9340.

In FIG. 77, an illustrative method 9350 of assembling a vented nuclearfission fuel module starts at a block 9360. At a block 9370, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9380, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9390, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. The method stops ata block 9400.

In FIG. 78, an illustrative method 9410 of assembling a vented nuclearfission fuel module starts at a block 9420. At a block 9430, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9440, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9450, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9460, aflexible diaphragm is coupled to the valve for allowing movement of thevalve to a closed position. The method stops at a block 9470.

In FIG. 79, an illustrative method 9471 of assembling a vented nuclearfission fuel module starts at a block 9472. At a block 9473, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9474, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9475, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9476, acap is mounted on the valve. At a block 9477, a manipulator extendableto the cap for manipulating the cap is received. The method stops at ablock 9478.

In FIG. 80, an illustrative method 9480 of assembling a vented nuclearfission fuel module starts at a block 9482. At a block 9484, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9486, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9488, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9490, amanipulator extendable to the valve for manipulating the valve isreceived. The method stops at a block 9520.

In FIG. 80A, an illustrative method 9530 of assembling a vented nuclearfission fuel module starts at a block 9540. At a block 9550, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9560, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9570, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9580, anarticulated manipulator arm is extended to the plenum. At a block 9590,a receptacle is carried on the articulated manipulator arm, thereceptacle being engageable with the plenum for receiving the gaseousfission product from the plenum. The method stops at a block 9600.

In FIG. 81, an illustrative method 9610 of assembling a vented nuclearfission fuel module starts at a block 9620. At a block 9630, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9640, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9650, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9660, anarticulated manipulator arm is extended to the plenum. At a block 9670,a receptacle is carried on the articulated manipulator arm, thereceptacle being engageable with the plenum for receiving the gaseousfission product from the plenum. At a block 9680, a suction device iscarried. The method stops at a block 9690.

In FIG. 82, an illustrative method 9700 of assembling a vented nuclearfission fuel module starts at a block 9710. At a block 9720, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9730, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9740, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9750, avalve is disposed that is responsive to a pressure in the plenum. Themethod stops at a block 9760.

In FIG. 83, an illustrative method 9770 of assembling a vented nuclearfission fuel module starts at a block 9780. At a block 9790, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9800, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9810, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9820, avalve is disposed that is responsive to a type of gaseous fissionproduct in the plenum. The method stops at a block 9830.

In FIG. 84, an illustrative method 9840 of assembling a vented nuclearfission fuel module starts at a block 9850. At a block 9860, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9870, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9880, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9890, asensor is disposed into operative communication with the plenum. Themethod stops at a block 9900.

In FIG. 85, an illustrative method 9910 of assembling a vented nuclearfission fuel module starts at a block 9920. At a block 9930, the methodcomprises receiving a nuclear fission fuel element capable of generatinga gaseous fission product. At a block 9940, a valve body is coupled tothe nuclear fission fuel element, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 9950, avalve is disposed in communication with the plenum for controllablyventing the gaseous fission product from the plenum. At a block 9960, asensor is disposed into operative communication with the plenum. At ablock 9970, a sensor is disposed for sensing a pressure in the plenum.The method stops at a block 9980.

In FIG. 85A, an illustrative method 9990 of assembling a vented nuclearfission fuel module starts at a block 10000. At a block 10010, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10020, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10030, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10040, a sensor is disposed into operative communication with theplenum. At a block 10050, a sensor is disposed for sensing a type ofgaseous fission product in the plenum. The method stops at a block10060.

In FIG. 85B, an illustrative method 10070 of assembling a vented nuclearfission fuel module starts at a block 10080. At a block 10090, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10100, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10110, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10120, a sensor is disposed into operative communication with theplenum. At a block 10130, a sensor is disposed for sensing a radioactivefission product in the plenum. The method stops at a block 10140.

In FIG. 85C, an illustrative method 10150 of assembling a vented nuclearfission fuel module starts at a block 10160. At a block 10170, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10180, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10190, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10200, a sensor is disposed into operative communication with theplenum. At a block 10210, a radiation sensor is disposed into theplenum. The method stops at a block 10220.

In FIG. 85D, an illustrative method 10230 of assembling a vented nuclearfission fuel module starts at a block 10240. At a block 10250, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10260, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10270, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10280, a sensor is disposed into operative communication with theplenum. At a block 10290, a chemical sensor is disposed into the plenum.The method stops at a block 10300.

In FIG. 85E, an illustrative method 10310 of assembling a vented nuclearfission fuel module starts at a block 10320. At a block 10330, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10340, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10350, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10360, a sensor is disposed into operative communication with theplenum. At a block 10370, an optical sensor is disposed into the plenum.The method stops at a block 10380.

In FIG. 85F, an illustrative method 10390 of assembling a vented nuclearfission fuel module starts at a block 10400. At a block 10410, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10420, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10430, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10440, a sensor is disposed into operative communication with theplenum. At a block 10450, a transmitter is disposed. The method stops ata block 10460.

In FIG. 86, an illustrative method 10470 of assembling a vented nuclearfission fuel module starts at a block 10480. At a block 10490, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10500, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10510, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10520, a sensor is disposed into operative communication with theplenum. At a block 10525, a transmitter is disposed. At a block 10530, aradio frequency transmitter is disposed into the plenum. The methodstops at a block 10540.

In FIG. 87, an illustrative method 10550 of assembling a vented nuclearfission fuel module starts at a block 10560. At a block 10570, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10580, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10590, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10600, a sensor is disposed into operative communication with theplenum. At a block 10605, a transmitter is disposed. At a block 10610, atransmitter is disposed that is configured to transmit a signal from thesensor. The method stops at a block 10620.

In FIG. 87A, an illustrative method 10630 of assembling a vented nuclearfission fuel module starts at a block 10640. At a block 10650, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10660, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10670, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10680, a sensor is disposed into operative communication with theplenum. At a block 10685, a transmitter is disposed. At a block 10690, atransmitter is disposed that is configured to transmit an identificationsignal identifying the valve body. The method stops at a block 10700.

In FIG. 88, an illustrative method 10710 of assembling a vented nuclearfission fuel module starts at a block 10720. At a block 10730, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10740, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10750, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10760, a sensor is disposed into operative communication with theplenum. At a block 10765, a transmitter is disposed. At a block 10770,an electrical signal carrier is disposed. The method stops at a block10780.

In FIG. 88A, an illustrative method 10781 of assembling a vented nuclearfission fuel module starts at a block 10782. At a block 10783, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10784, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10785, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10786, a sensor is disposed into operative communication with theplenum. At a block 10787, a transmitter is disposed. At a block 10788,an optical fiber is disposed. The method stops at a block 10789.

In FIG. 89, an illustrative method 10790 of assembling a vented nuclearfission fuel module starts at a block 10800. At a block 10810, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10820, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10830, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10840, the nuclear fission fuel element, the valve body and thevalve are disposed in a thermal neutron reactor core. The method stopsat a block 10850.

In FIG. 90, an illustrative method 10860 of assembling a vented nuclearfission fuel module starts at a block 10870. At a block 10880, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10890, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10900, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10910, the nuclear fission fuel element, the valve body and thevalve are disposed in a fast neutron reactor core. The method stops at ablock 10920.

In FIG. 91, an illustrative method 10930 of assembling a vented nuclearfission fuel module starts at a block 10940. At a block 10950, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 10960, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block10970, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 10980, the nuclear fission fuel element, the valve body and thevalve are disposed in a fast neutron breeder reactor core. The methodstops at a block 10990.

In FIG. 92, an illustrative method 11000 of assembling a vented nuclearfission fuel module starts at a block 11010. At a block 11020, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11030, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11040, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11050, the nuclear fission fuel element, the valve body and thevalve are disposed in a traveling wave fast neutron reactor core. Themethod stops at a block 11060.

In FIG. 92A, an illustrative method 11070 of assembling a vented nuclearfission fuel module starts at a block 11080. At a block 11090, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11100, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11110, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11120, a canister surrounding the fuel element is received. Themethod stops at a block 11130.

In FIG. 93, an illustrative method 11140 of assembling a vented nuclearfission fuel module starts at a block 11150. At a block 11160, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11170, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11180, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11190, a canister surrounding the fuel element is received. At ablock 11200, a canister having a bottom portion defining a first openingis received. At a block 11210, a canister having a side portion defininga second opening is received. The method stops at a block 11220.

In FIG. 94, an illustrative method 11230 of assembling a vented nuclearfission fuel module starts at a block 11240. At a block 11250, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11260, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11270, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11280, a canister surrounding the fuel element is received. At ablock 11290, a canister having a bottom portion defining a first openingis received. At a block 11300, a canister having a side portion defininga second opening is received. At a block 11310, a canister is receivedhaving a tube sheet therein having a contour shaped for guiding acoolant along a coolant flow path extending from the first opening andthrough the second opening. The method stops at a block 11320.

In FIG. 94A, an illustrative method 11330 of assembling a vented nuclearfission fuel module starts at a block 11340. At a block 11350, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11360, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11370, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11380, a canister surrounding the fuel element is received. At ablock 11390, a canister having a bottom portion defining a first openingis received. At a block 11400, a canister having a side portion defininga second opening is received. At a block 11410, a canister is receivedhaving a ceramic tube sheet therein having a contour shaped for guidinga coolant along a coolant flow path extending from the first opening andthrough the second opening. The method stops at a block 11420.

In FIG. 95, an illustrative method 11430 of assembling a vented nuclearfission fuel module starts at a block 11440. At a block 11450, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11460, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11470, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11480, a reservoir is coupled to the valve for receiving thegaseous fission product vented by the valve. The method stops at a block11490.

In FIG. 96, an illustrative method 11500 of assembling a vented nuclearfission fuel module starts at a block 11510. At a block 11520, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11530, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11540, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11550, a reservoir is coupled to the valve for receiving thegaseous fission product vented by the valve. At a block 11560, a filteris coupled to the reservoir for separating a condensed phase fissionproduct from the gaseous fission product. The method stops at a block11570.

In FIG. 96A, an illustrative method 11580 of assembling a vented nuclearfission fuel module starts at a block 11590. At a block 11600, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11610, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11620, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11630, a reservoir is coupled to the valve for receiving thegaseous fission product vented by the valve. At a block 11640, a filteris coupled to the reservoir for separating a condensed phase fissionproduct from the gaseous fission product. At a block 11650, a HEPAfilter is coupled to the reservoir for separating a condensed phasefission product from the gaseous fission product. The method stops at ablock 11660.

In FIG. 96B, an illustrative method 11670 of assembling a vented nuclearfission fuel module starts at a block 11680. At a block 11690, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11700, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11710, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11720, a reservoir is coupled to the valve for receiving thegaseous fission product vented by the valve. At a block 11730, a filteris coupled to the reservoir for separating a condensed phase fissionproduct from the gaseous fission product. At a block 11740, asemi-permeable membrane is coupled to the reservoir for separating acondensed phase fission product from the gaseous fission product. Themethod stops at a block 11750.

In FIG. 96C, an illustrative method 11760 of assembling a vented nuclearfission fuel module starts at a block 11770. At a block 11780, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11790, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11800, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11810, a reservoir is coupled to the valve for receiving thegaseous fission product vented by the valve. At a block 11820, a filteris coupled to the reservoir for separating a condensed phase fissionproduct from the gaseous fission product. At a block 11830, anelectrostatic collector is coupled to the reservoir for separating acondensed phase fission product from the gaseous fission product. Themethod stops at a block 11840.

In FIG. 96D, an illustrative method 11850 of assembling a vented nuclearfission fuel module starts at a block 11860. At a block 11870, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11880, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11890, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11900, a reservoir is coupled to the valve for receiving thegaseous fission product vented by the valve. At a block 11910, a filteris coupled to the reservoir for separating a condensed phase fissionproduct from the gaseous fission product. At a block 11920, a cold trapis coupled to the reservoir for separating a condensed phase fissionproduct from the gaseous fission product. The method stops at a block11930.

In FIG. 96E, an illustrative method 11940 of assembling a vented nuclearfission fuel module starts at a block 11950. At a block 11960, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 11970, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block11980, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 11990, a reservoir is coupled to the valve for receiving thegaseous fission product vented by the valve. At a block 12000, thereservoir is coupled to a reactor vessel. At a block 12010, a reservoiris coupled that is capable of being decoupled from the reactor vesselfor removing the gaseous fission product from the reactor vessel. Themethod stops at a block 12020.

In FIG. 96F, an illustrative method 12030 of assembling a vented nuclearfission fuel module starts at a block 12040. At a block 12050, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 12060, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block12070, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 12080, a reservoir is coupled to the valve for receiving thegaseous fission product vented by the valve. At a block 12090, thereservoir is coupled to a reactor vessel. At a block 12100, a reservoiris coupled that is capable of remaining coupled to the reactor vesselfor storing the gaseous fission product at the reactor vessel. Themethod stops at a block 12110.

In FIG. 97, an illustrative method 12120 of assembling a vented nuclearfission fuel module starts at a block 12130. At a block 12140, themethod comprises receiving a nuclear fission fuel element capable ofgenerating a gaseous fission product. At a block 12150, a valve body iscoupled to the nuclear fission fuel element, the valve body defining aplenum therein for receiving the gaseous fission product. At a block12160, a valve is disposed in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 12170, a controller is coupled to the valve for controllingoperation of the valve. The method stops at a block 12180.

In FIG. 98, an illustrative method 12190 of assembling a vented nuclearfission fuel module starts at a block 12200. At a block 12210, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block12220, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12230, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12240, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12250, a removable cap is threadably mounted onthe valve. The method stops at block 12260.

In FIG. 98A, an illustrative method 12270 of assembling a vented nuclearfission fuel module starts at a block 12280. At a block 12290, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block12300, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12310, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12320, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12330, a removable cap is threadably mounted onthe valve. At a block 12340, a flexible diaphragm is coupled that iscapable of moving the valve to a closed position. The method stops at ablock 12350.

In FIG. 99, an illustrative method 12360 of assembling a vented nuclearfission fuel module starts at a block 12370. At a block 12380, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block12390, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12400, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12410, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12420, a removable cap is threadably mounted onthe valve. At a block 12430, an articulated manipulator arm is receivedthat is extendable to the cap for threadably dismounting the cap fromthe valve. The method stops at a block 12440.

In FIG. 100, an illustrative method 12450 of assembling a vented nuclearfission fuel module starts at a block 12460. At a block 12470, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block12480, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12490, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12500, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12510, a removable cap is threadably mounted onthe valve. At a block 12520, an articulated manipulator arm is receivedthat is extendable to the valve for operating the valve. The methodstops at a block 12530.

In FIG. 101, an illustrative method 12540 of assembling a vented nuclearfission fuel module starts at a block 12550. At a block 12560, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block12570, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12580, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12590, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12600, a removable cap is threadably mounted onthe valve. At a block 12610, an articulated manipulator arm is receivedthat is extendable to the plenum. At a block 12620, a receptacle iscarried on the articulated manipulator arm and is engageable with theplenum for receiving the gaseous fission product controllably ventedfrom the plenum. The method stops at a block 12630.

In FIG. 101A, an illustrative method 12640 of assembling a ventednuclear fission fuel module starts at a block 12650. At a block 12660,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 12670, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12680, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12690, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12700, a removable cap is threadably mounted onthe valve. At a block 12710, an articulated manipulator arm is receivedthat is extendable to the plenum. At a block 12720, a receptacle iscarried on the articulated manipulator arm and is engageable with theplenum for receiving the gaseous fission product controllably ventedfrom the plenum. At a block 12730, a suction device is carried. Themethod stops at a block 12740.

In FIG. 102, an illustrative method 12750 of assembling a vented nuclearfission fuel module starts at a block 12760. At a block 12770, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block12780, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12790, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12800, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12810, a removable cap is threadably mounted onthe valve. At a block 12820, a valve is disposed that is responsive to apressure in the plenum. The method stops at a block 12830.

In FIG. 103, an illustrative method 12840 of assembling a vented nuclearfission fuel module starts at a block 12850. At a block 12860, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block12870, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12880, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12890, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12900, a removable cap is threadably mounted onthe valve. At a block 12910, a valve is disposed that is responsive to atype of gaseous fission product in the plenum. The method stops at ablock 12920.

In FIG. 104, an illustrative method 12930 of assembling a vented nuclearfission fuel module starts at a block 12940. At a block 12950, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block12960, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 12970, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 12980, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 12990, a removable cap is threadably mounted onthe valve. At a block 13000, a sensor is disposed into operativecommunication with the plenum. The method stops at a block 13010.

In FIG. 105, an illustrative method 13020 of assembling a vented nuclearfission fuel module starts at a block 13030. At a block 13040, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block13050, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13060, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13070, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13080, a removable cap is threadably mounted onthe valve. At a block 13090, a sensor is disposed into operativecommunication with the plenum. At a block 13100, a sensor is disposedfor sensing a pressure in the plenum. The method stops at a block 13110.

In FIG. 106, an illustrative method 13120 of assembling a vented nuclearfission fuel module starts at a block 13130. At a block 13140, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block13150, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13160, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13170, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13180, a removable cap is threadably mounted onthe valve. At a block 13190, a sensor is disposed into operativecommunication with the plenum. At a block 13200, a sensor is disposedfor sensing a type of gaseous fission product in the plenum. The methodstops at a block 13210.

In FIG. 106A, an illustrative method 13220 of assembling a ventednuclear fission fuel module starts at a block 13230. At a block 13240,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 13250, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13260, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13270, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13280, a removable cap is threadably mounted onthe valve. At a block 13290, a sensor is disposed into operativecommunication with the plenum. At a block 13300, a sensor is disposedfor sensing a radioactive fission product. The method stops at a block13310.

In FIG. 106B, an illustrative method 13320 of assembling a ventednuclear fission fuel module starts at a block 13330. At a block 13340,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 13350, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13360, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13370, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13380, a removable cap is threadably mounted onthe valve. At a block 13390, a sensor is disposed into operativecommunication with the plenum. At a block 13400, a radiation sensor isdisposed. The method stops at a block 13410.

In FIG. 106C, an illustrative method 13420 of assembling a ventednuclear fission fuel module starts at a block 13430. At a block 13440,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 13450, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13460, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13470, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13480, a removable cap is threadably mounted onthe valve. At a block 13490, a sensor is disposed into operativecommunication with the plenum. At a block 13500, a chemical sensor isdisposed. The method stops at a block 13510.

In FIG. 106D, an illustrative method 13520 of assembling a ventednuclear fission fuel module starts at a block 13530. At a block 13540,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 13550, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13560, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13570, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13580, a removable cap is threadably mounted onthe valve. At a block 13590, a sensor is disposed into operativecommunication with the plenum. At a block 13600, an optical sensor isdisposed. The method stops at a block 13610.

In FIG. 106E, an illustrative method 13620 of assembling a ventednuclear fission fuel module starts at a block 13630. At a block 13640,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 13650, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13660, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13670, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13680, a removable cap is threadably mounted onthe valve. At a block 13690, a sensor is disposed into operativecommunication with the plenum. At a block 13700, a transmitter isdisposed. The method stops at a block 13710.

In FIG. 107, an illustrative method 13720 of assembling a vented nuclearfission fuel module starts at a block 13730. At a block 13740, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block13750, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13760, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13770, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13780, a removable cap is threadably mounted onthe valve. At a block 13790, a sensor is disposed into operativecommunication with the plenum. At a block 13795, a transmitter isdisposed. At a block 13800, a radio frequency transmitter is disposed.The method stops at a block 13810.

In FIG. 108, an illustrative method 13820 of assembling a vented nuclearfission fuel module starts at a block 13830. At a block 13840, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block13850, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13860, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13870, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13880, a removable cap is threadably mounted onthe valve. At a block 13890, a sensor is disposed into operativecommunication with the plenum. At a block 13895, a transmitter isdisposed. At a block 13900, a transmitter is disposed that is configuredto transmit a signal from the sensor. The method stops at a block 13910.

In FIG. 109, an illustrative method 13920 of assembling a vented nuclearfission fuel module starts at a block 13930. At a block 13940, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block13950, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 13960, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 13970, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 13980, a removable cap is threadably mounted onthe valve. At a block 13990, a sensor is disposed into operativecommunication with the plenum. At a block 13995, a transmitter isdisposed. At a block 14000, a transmitter is disposed that is configuredto transmit an identification signal identifying the valve body. Themethod stops at a block 14010.

In FIG. 110, an illustrative method 14020 of assembling a vented nuclearfission fuel module starts at a block 14030. At a block 14040, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block14050, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14060, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14070, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14080, a removable cap is threadably mounted onthe valve. At a block 14090, a sensor is disposed into operativecommunication with the plenum. At a block 14095, a transmitter isdisposed. At a block 14100, an electrical signal carrier is disposed.The method stops at a block 14110.

In FIG. 110A, an illustrative method 14111 of assembling a ventednuclear fission fuel module starts at a block 14112. At a block 14113,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 14114, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14115, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14116, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14117, a removable cap is threadably mounted onthe valve. At a block 14118, a sensor is disposed into operativecommunication with the plenum. At a block 14119, a transmitter isdisposed. At a block 14120, an optical fiber is disposed. The methodstops at a block 14121.

In FIG. 111, an illustrative method 14122 of assembling a vented nuclearfission fuel module starts at a block 14130. At a block 14140, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block14150, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14160, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14170, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14180, a removable cap is threadably mounted onthe valve. At a block 14190, a vented nuclear fission fuel module isdefined by interconnecting at least one of the plurality of nuclearfission fuel element bundles, the valve body, the valve, the diaphragmand the removable cap. The method stops at a block 14200.

In FIG. 111A, an illustrative method 14210 of assembling a ventednuclear fission fuel module starts at a block 14220. At a block 14230,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 14240, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14250, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14260, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14270, a removable cap is threadably mounted onthe valve. At a block 14280, a vented nuclear fission fuel module isdefined by interconnecting at least one of the plurality of nuclearfission fuel element bundles, the valve body, the valve, the diaphragmand the removable cap. At a block 14290, a vented nuclear fission fuelmodule is defined that is capable of being disposed in a thermal neutronreactor core. The method stops at a block 14300.

In FIG. 112, an illustrative method 14310 of assembling a vented nuclearfission fuel module starts at a block 14320. At a block 14330, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block14340, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14350, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14360, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14370, a removable cap is threadably mounted onthe valve. At a block 14380, a vented nuclear fission fuel module isdefined by interconnecting at least one of the plurality of nuclearfission fuel element bundles, the valve body, the valve, the diaphragmand the removable cap. At a block 14390, a vented nuclear fission fuelmodule is defined that is capable of being disposed in a fast neutronreactor core. The method stops at a block 14400.

In FIG. 113, an illustrative method 14410 of assembling a vented nuclearfission fuel module starts at a block 14420. At a block 14430, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block14440, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14450, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14460, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14470, a removable cap is threadably mounted onthe valve. At a block 14480, a vented nuclear fission fuel module isdefined by interconnecting at least one of the plurality of nuclearfission fuel element bundles, the valve body, the valve, the diaphragmand the removable cap. At a block 14490, a vented nuclear fission fuelmodule is defined that is capable of being disposed in a fast neutronbreeder reactor core. The method stops at a block 14500.

In FIG. 114, an illustrative method 14510 of assembling a vented nuclearfission fuel module starts at a block 14520. At a block 14530, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block14540, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14550, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14560, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14570, a removable cap is threadably mounted onthe valve. At a block 14580, a vented nuclear fission fuel module isdefined by interconnecting at least one of the plurality of nuclearfission fuel element bundles, the valve body, the valve, the diaphragmand the removable cap. At a block 14590, a vented nuclear fission fuelmodule is defined that is capable of being disposed in a traveling wavefast neutron reactor core. The method stops at a block 14600.

In FIG. 114A, an illustrative method 14610 of assembling a ventednuclear fission fuel module starts at a block 14620. At a block 14630,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 14640, a valve body is coupled to each of the plurality of nuclearfission fuel element bundles, the valve body defining a plenum thereinfor receiving the gaseous fission product. At a block 14650, a valve isdisposed in the valve body and in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 14660, a flexible diaphragm is coupled to the valve for moving thevalve. At a block 14670, a removable cap is threadably mounted on thevalve. At a block 14680, a canister surrounding at least one of theplurality of fuel element bundles is received. The method stops at ablock 14690.

In FIG. 115, an illustrative method 14700 of assembling a vented nuclearfission fuel module starts at a block 14710. At a block 14720, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block14730, a valve body is coupled to each of the plurality of nuclearfission fuel element bundles, the valve body defining a plenum thereinfor receiving the gaseous fission product. At a block 14740, a valve isdisposed in the valve body and in communication with the plenum forcontrollably venting the gaseous fission product from the plenum. At ablock 14750, a flexible diaphragm is coupled to the valve for moving thevalve. At a block 14760, a removable cap is threadably mounted on thevalve. At a block 14770, a canister surrounding at least one of theplurality of fuel element bundles is received. At a block 14780, acanister having a bottom portion defining a flow opening is received. Ata block 14790, a canister having a side portion defining a flow port isreceived. The method stops at a block 14800.

In FIG. 116, an illustrative method 14810 of assembling a vented nuclearfission fuel module starts at a block 14820. At a block 14830, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block14840, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14850, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14860, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14870, a removable cap is threadably mounted onthe valve. At a block 14880, a canister surrounding at least one of theplurality of fuel element bundles is received. At a block 14890, acanister having a bottom portion defining a flow opening is received. Ata block 14900, a canister having a side portion defining a flow port isreceived. At a block 14910, a canister is received including a tubesheet therein having a contour on an underside surface thereof shapedfor guiding a coolant along a curved coolant flow path extending fromthe flow opening and through the flow port. The method stops at a block14920.

In FIG. 116A, an illustrative method 14930 of assembling a ventednuclear fission fuel module starts at a block 14940. At a block 14950,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 14960, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 14970, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 14980, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 14990, a removable cap is threadably mounted onthe valve. At a block 15000, a canister surrounding at least one of theplurality of fuel element bundles is received. At a block 15010, acanister having a bottom portion defining a flow opening is received. Ata block 15020, a canister having a side portion defining a flow port isreceived. At a block 15030, a canister is received including a ceramictube sheet therein for dissipating heat and having a contour on anunderside thereof shaped for guiding a coolant along a curved coolantflow path extending from the flow opening and through the flow portextending from the flow opening and through the flow port. The methodstops at a block 15040.

In FIG. 117, an illustrative method 15050 of assembling a vented nuclearfission fuel module starts at a block 15060. At a block 15070, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block15080, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15090, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15100, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15110, a removable cap is threadably mounted onthe valve. At a block 15120, a reservoir is coupled to the valve forreceiving the gaseous fission product vented by the valve. The methodstops at a block 15130.

In FIG. 118, an illustrative method 15140 of assembling a vented nuclearfission fuel module starts at a block 15150. At a block 15160, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block15170, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15180, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15190, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15200, a removable cap is threadably mounted onthe valve. At a block 15210, a reservoir is coupled to the valve forreceiving the gaseous fission product vented by the valve. At a block15220, a reservoir is coupled having a removable filter for separatingand capturing a condensed phase fission product from the gaseous fissionproduct. The method stops at a block 15230.

In FIG. 118A, an illustrative method 15240 of assembling a ventednuclear fission fuel module starts at a block 15250. At a block 15260,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 15270, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15280, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15290, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15300, a removable cap is threadably mounted onthe valve. At a block 15310, a reservoir is coupled to the valve forreceiving the gaseous fission product vented by the valve. At a block15320, a reservoir is coupled having a removable filter for separatingand capturing a condensed phase fission product from the gaseous fissionproduct. At a block 15330, a HEPA filter is coupled. The method stops ata block 15340.

In FIG. 118B, an illustrative method 15350 of assembling a ventednuclear fission fuel module starts at a block 15360. At a block 15370,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 15380, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15390, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15400, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15410, a removable cap is threadably mounted onthe valve. At a block 15420, a reservoir is coupled to the valve forreceiving the gaseous fission product vented by the valve. At a block15430, a reservoir is coupled having a removable filter for separatingand capturing a condensed phase fission product from the gaseous fissionproduct. At a block 15440, a semi-permeable membrane is coupled. Themethod stops at a block 15450.

In FIG. 118C, an illustrative method 15460 of assembling a ventednuclear fission fuel module starts at a block 15470. At a block 15480,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 15490, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15500, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15510, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15520, a removable cap is threadably mounted onthe valve. At a block 15530, a reservoir is coupled to the valve forreceiving the gaseous fission product vented by the valve. At a block15540, a reservoir is coupled having a removable filter for separatingand capturing a condensed phase fission product from the gaseous fissionproduct. At a block 15550, an electrostatic collector is coupled. Themethod stops at a block 15560.

In FIG. 118D, an illustrative method 15570 of assembling a ventednuclear fission fuel module starts at a block 15580. At a block 15590,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 15600, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15610, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15620, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15630, a removable cap is threadably mounted onthe valve. At a block 15640, a reservoir is coupled to the valve forreceiving the gaseous fission product vented by the valve. At a block15650, a reservoir is coupled having a removable filter for separatingand capturing a condensed phase fission product from the gaseous fissionproduct. At a block 15660, a cold trap is coupled. The method stops at ablock 15670.

In FIG. 119, an illustrative method 15680 of assembling a vented nuclearfission fuel module starts at a block 15690. At a block 15700, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block15710, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15720, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15730, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15740, a removable cap is threadably mounted onthe valve. At a block 15750, a reservoir is coupled to the valve forreceiving the gaseous fission product vented by the valve. At a block15760, the reservoir is coupled to a reactor vessel. At a block 15770, areservoir is coupled that is capable of being decoupled from the reactorvessel for removing the gaseous fission product from the reactor vessel.The method stops at a block 15780.

In FIG. 119A, an illustrative method 15790 of assembling a ventednuclear fission fuel module starts at a block 15800. At a block 15810,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 15820, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15830, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15840, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15850, a removable cap is threadably mounted onthe valve. At a block 15860, a reservoir is coupled to the valve forreceiving the gaseous fission product vented by the valve. At a block15870, the reservoir is coupled to a reactor vessel. At a block 15880, areservoir is coupled that is capable of remaining coupled to the reactorvessel for storing the gaseous fission product at the reactor vessel.The method stops at a block 15890.

In FIG. 119B, an illustrative method 15900 of assembling a ventednuclear fission fuel module starts at a block 15910. At a block 15920,the method comprises receiving a plurality of nuclear fission fuelelement bundles capable of generating a gaseous fission product. At ablock 15930, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 15940, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 15950, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 15960, a removable cap is threadably mounted onthe valve. At a block 15970, a valve is disposed that is operable tocontrollably vent the gaseous fission product according to apredetermined release rate for minimizing size of an associated gaseousfission product clean-up system. The method stops at a block 15980.

In FIG. 120, an illustrative method 15990 of assembling a vented nuclearfission fuel module starts at a block 16000. At a block 16010, themethod comprises receiving a plurality of nuclear fission fuel elementbundles capable of generating a gaseous fission product. At a block16020, a valve body is coupled to at least one of the plurality ofnuclear fission fuel element bundles, the valve body defining a plenumtherein for receiving the gaseous fission product. At a block 16030, avalve is disposed in the valve body and in communication with the plenumfor controllably venting the gaseous fission product from the plenum. Ata block 16040, a flexible diaphragm is coupled to the valve for movingthe valve. At a block 16050, a removable cap is threadably mounted onthe valve. At a block 16060, a controller is coupled to the valve forcontrolling operation of the valve. The method stops at a block 16070.

One skilled in the art will recognize that the herein describedcomponents (e.g., operations), devices, objects, and the discussionaccompanying them are used as examples for the sake of conceptualclarity and that various configuration modifications are contemplated.Consequently, as used herein, the specific exemplars set forth and theaccompanying discussion are intended to be representative of their moregeneral classes. In general, use of any specific exemplar is intended tobe representative of its class, and the non-inclusion of specificcomponents (e.g., operations), devices, and objects should not be takenas limiting.

Moreover, those skilled in the art will appreciate that the foregoingspecific illustrative processes and/or devices and/or technologies arerepresentative of more general processes and/or devices and/ortechnologies taught elsewhere herein, such as in the claims filedherewith and/or elsewhere in the present application.

While particular aspects of the present subject matter described hereinhave been shown and described, it will be apparent to those skilled inthe art that, based upon the teachings herein, changes and modificationsmay be made without departing from the subject matter described hereinand its broader aspects and, therefore, the appended claims are toencompass within their scope all such changes and modifications as arewithin the true spirit and scope of the subject matter described herein.It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to claims containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that typically a disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms unless context dictates otherwise. For example, the phrase “Aor B” will be typically understood to include the possibilities of “A”or “B” or “A and B.”

With respect to the appended claims, those skilled in the art willappreciate that recited operations therein may generally be performed inany order. Also, although various operational flows are presented in asequence(s), it should be understood that the various operations may beperformed in other orders than those which are illustrated, or may beperformed concurrently. Examples of such alternate orderings may includeoverlapping, interleaved, interrupted, reordered, incremental,preparatory, supplemental, simultaneous, reverse, or other variantorderings, unless context dictates otherwise. Furthermore, terms like“responsive to,” “related to,” or other past-tense adjectives aregenerally not intended to exclude such variants, unless context dictatesotherwise.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.Moreover, the various aspects and embodiments disclosed herein are forpurposes of illustration and are not intended to be limiting, with thetrue scope and spirit being indicated by the following claims.

What is claimed is:
 1. A method comprising: generating a gaseous fissionproduct with a nuclear fission fuel element disposed in a reactorvessel; receiving the gaseous fission product into a plenum defined by avalve body associated with the nuclear fission fuel element disposed ina reactor vessel; and controllably venting the gaseous fission productfrom the plenum by operating a valve in communication with the plenum bydisplacing the valve by moving a flexible diaphragm coupled to thevalve.
 2. The method of claim 1, further comprising: mounting a cap onthe valve; and extending a manipulator to the cap for manipulating thecap.
 3. The method of claim 1, further comprising extending amanipulator to the valve for manipulating the valve.
 4. The method ofclaim 1, further comprising: extending an articulated manipulator arm tothe plenum; and carrying a receptacle on the articulated manipulatorarm, the receptacle engageable with the plenum for receiving the gaseousfission product controllably vented from the plenum.
 5. The method ofclaim 1, wherein controllably venting the gaseous fission product fromthe plenum by operating venting means in communication with the plenumcomprises controllably venting the gaseous fission product from theplenum by operating a valve responsive to a parameter chosen frompressure in the plenum and a type of gaseous fission product in theplenum.
 6. The method of claim 1, further comprising sensing a parameterwith a sensor in operative communication with the plenum.
 7. The methodof claim 6, wherein the parameter includes a parameter chosen frompressure in the plenum, a type of gaseous fission product in the plenum,and a radioactive fission product in the plenum.
 8. The method of claim6, further comprising transmitting a signal from the sensor.
 9. Themethod of claim 8, wherein transmitting a signal from the sensorincludes transmitting an identification signal identifying the valvebody.
 10. The method of claim 1, further comprising receiving thegaseous fission product into a reservoir coupled to the venting means.11. The method of claim 10, wherein receiving the gaseous fissionproduct into a reservoir comprises separating a condensed phase fissionproduct from the gaseous fission product by passing the gaseous fissionproduct through a filter.
 12. The method of claim 11, wherein separatinga condensed phase fission product from the gaseous fission product bypassing the gaseous fission product through a filter comprisesseparating a condensed phase fission product from the gaseous fissionproduct by passing the gaseous fission product through a semi-permeablemembrane.
 13. The method of claim 11, wherein separating a condensedphase fission product solid from the gaseous fission product by passingthe gaseous fission product through a filter comprises separating acondensed phase fission product from the gaseous fission product bypassing the gaseous fission product through an electrostatic collector.14. The method of claim 11, wherein separating a condensed phase fissionproduct solid from the gaseous fission product by passing the gaseousfission product through a filter reservoir comprises separating acondensed phase fission product from the gaseous fission product bypassing the gaseous fission product through a cold trap.
 15. The methodof claim 10, wherein receiving the gaseous fission product into areservoir comprises receiving the gaseous fission product into areservoir coupled to a reactor vessel; and wherein receiving the gaseousfission product into a reservoir comprises receiving the gaseous fissionproduct into a reservoir capable of being decoupled from the reactorvessel for removing the gaseous fission product from the reactor vessel.16. The method of claim 10, wherein receiving the gaseous fissionproduct into a reservoir comprises receiving the gaseous fission productinto a reservoir coupled to a reactor vessel; and wherein receiving thegaseous fission product into a reservoir comprises receiving the gaseousfission product into a reservoir capable of remaining coupled to thereactor vessel for storing the gaseous fission product at the reactorvessel.
 17. The method of claim 1, further comprising operating acoolant system in operative communication with the venting means forreceiving the gaseous fission product controllably vented by the ventingmeans.
 18. The method of claim 1, further comprising removing thegaseous fission product from the coolant system to a removal system inoperative communication with the coolant system.
 19. The method of claim1, wherein operating venting means associated with the nuclear fissionfuel element comprises operating a reclosable valve.
 20. The method ofclaim 1, wherein operating venting means associated with the nuclearfission fuel element comprises operating a sealably reclosable valve.21. The method of claim 1, further comprising controlling operation ofthe venting means by operating a controller coupled to the ventingmeans.
 22. A method of operating a nuclear fission reactor, comprising:generating a gaseous fission product with a plurality of nuclear fissionfuel element bundles disposed in a reactor vessel; receiving the gaseousfission product into a plenum defined by at least one of a plurality ofvalve bodies associated with respective ones of the plurality of nuclearfission fuel element bundles disposed in the reactor vessel;controllably venting the gaseous fission product from the plenum byoperating a valve disposed in the at least one of the plurality of valvebodies, the valve being in communication with the plenum; displacing thevalve by allowing movement of a flexible diaphragm coupled to the valve;and threadably mounting a cap on the valve.
 23. The method of claim 22,further comprising activating a plurality of nuclear fission fuelelement bundles associated with respective ones of the plurality ofvalve bodies, at least one of the plurality of nuclear fission fuelelement bundles being capable of generating the gaseous fission product.24. The method of claim 22, wherein controllably venting the gaseousfission product comprises allowing movement of a flexible diaphragmcapable of displacing the valve to a closed position.
 25. The method ofclaim 22, further comprising extending an articulated manipulator arm tothe cap for threadably dismounting the cap from the valve.
 26. Themethod of claim 22, further comprising extending an articulatedmanipulator arm to the valve for operating the valve.
 27. The method ofclaim 22, further comprising: extending an articulated manipulator armto the plenum; and carrying a receptacle on the articulated manipulatorarm, the receptacle being engageable with the plenum for receiving thegaseous fission product controllably vented from the plenum.
 28. Themethod of claim 22, wherein operating a valve in the at least one of theplurality of valve bodies comprises operating a valve responsive to aparameter chosen from pressure in the plenum and a type of gaseousfission product in the plenum.
 29. The method of claim 22, furthercomprising sensing a parameter with a sensor in operative communicationwith the plenum.
 30. The method of claim 29, wherein the parameterincludes a parameter chosen from pressure in the plenum, a type ofgaseous fission product in the plenum, and a radioactive fission productin the plenum.
 31. The method of claim 22, further comprisingtransmitting a signal from the sensor.
 32. The method of claim 31,transmitting a signal from the sensor includes transmitting anidentification signal identifying the valve body.
 33. The method ofclaim 22, further comprising receiving the gaseous fission product intoa reservoir coupled to the valve, the gaseous fission product beingvented by the valve.
 34. The method of claim 33, wherein receiving thegaseous fission product into the reservoir comprises separating acondensed phase fission product from the gaseous fission product bypassing the gaseous fission product through a filter disposed in thereservoir.
 35. The method of claim 34, wherein separating a condensedphase fission product from the gaseous fission product by passing thegaseous fission product through a filter disposed in the reservoircomprises separating a condensed phase fission product from the gaseousfission product by passing the gaseous fission product through asemi-permeable membrane.
 36. The method of claim 34, wherein separatinga condensed phase fission product from the gaseous fission product bypassing the gaseous fission product through a filter disposed in thereservoir comprises separating a condensed phase fission product fromthe gaseous fission product by passing the gaseous fission productthrough an electrostatic collector.
 37. The method of claim 34, whereinseparating a condensed phase fission product from the gaseous fissionproduct by passing the gaseous fission product through a filter disposedin the reservoir comprises separating a condensed phase fission productfrom the gaseous fission product by passing the gaseous fission productthrough a cold trap.
 38. The method of claim 33, wherein receiving thegaseous fission product into a reservoir comprises receiving the gaseousfission product into a reservoir coupled to a reactor vessel; andwherein receiving the gaseous fission product into a reservoir comprisesreceiving the gaseous fission product into a reservoir capable of beingdecoupled from the reactor vessel for removing the gaseous fissionproduct from the reactor vessel.
 39. The method of claim 33, whereinreceiving the gaseous fission product into a reservoir comprisesreceiving the gaseous fission product into a reservoir coupled to areactor vessel; and wherein receiving the gaseous fission product into areservoir comprises receiving the gaseous fission product into areservoir capable of remaining coupled to the reactor vessel for storingthe gaseous fission product at the reactor vessel.
 40. The method ofclaim 22, further comprising operating a coolant system in operativecommunication with the valve for receiving the gaseous fission productcontrollably vented by the valve.
 41. The method of claim 40, furthercomprising removing the gaseous fission product from the coolant systemto a removal system in operative communication with the coolant system.42. The method of claim 22, wherein controllably venting a gaseousfission product comprises operating a reclosable valve.
 43. The methodof claim 22, wherein controllably venting the gaseous fission productcomprises operating a sealably reclosable valve.
 44. The method of claim22, wherein controllably venting the gaseous fission product comprisesoperating the valve to controllably vent the gaseous fission productaccording to a predetermined release rate for minimizing size of anassociated gaseous fission product clean-up system.
 45. The method ofclaim 22, further comprising controllably operating the valve byoperating a controller coupled to the valve.